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TDMS Study 55301-05 Pathology Tables

NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97
Route: DOSED WATER                                                                                                Time: 11:10:29




       Facility:  TSI Mason Research

       Chemical CAS #:  110-86-1

       Lock Date:  12/15/94

       Cage Range:  All

       Reasons For Removal:    All

       Removal Date Range:     All

       Treatment Groups:       Include All




































Note:  Animals arranged according to CID number

                                                              Page   1


NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 6| 6| 6| 7| 3| 7| 6| 7| 7| 7| 5| 7| 7| 7| 4| 7| 7| 7| 7| 7| 6| 6|             
                             DAY ON TEST   | 2| 2| 2| 7| 2| 4| 2| 9| 2| 8| 2| 2| 2| 9| 2| 2| 2| 9| 2| 2| 2| 2| 2| 3| 8|             
                                           | 9| 9| 2| 3| 2| 9| 9| 9| 9| 7| 9| 9| 9| 6| 9| 9| 9| 3| 9| 9| 9| 9| 9| 6| 1|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS FEMALE                 | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|             
    0 PPM                                  | 1| 1| 1| 1| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Fibrous Histiocytoma, Metastatic,    |                                                                          |             
           Mesentery                       |                                                       X                  |             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Fibrous Histiocytoma, Metastatic,    |                                                                          |             
           Mesentery                       |                                                       X                  |             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Fibrous Histiocytoma, Metastatic,    |                                                                          |             
           Mesentery                       |                                                       X                  |             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Fibrous Histiocytoma, Metastatic,    |                                                                          |             
           Mesentery                       |                                                       X                  |             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Fibrous Histiocytoma, Metastatic,    |                                                                          |             
           Mesentery                       |                                                       X                  |             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Fibrous Histiocytoma, Metastatic,    |                                                                          |             
           Mesentery                       |                                                       X                  |             
      Hepatocellular Adenoma               |                                                                          |             
      Leukemia Mononuclear                 | X                          X  X                          X           X   |             
                                            __________________________________________________________________________|             
   Mesentery                               |    +              +        +                          +                  |             
      Fibrous Histiocytoma                 |                                                       X                  |             
                                            __________________________________________________________________________|             
   Oral Mucosa                             |    +                 +                                                   |             
      Pharyngeal, Squamous Cell Carcinoma  |    X                 X                                                   |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +|             
      Fibrous Histiocytoma, Metastatic,    |                                                                          |             
           Mesentery                       |                                                       X                  |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                                                      X   |             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Fibrous Histiocytoma, Metastatic,    |                                                                          |             
           Mesentery                       |                                                       X                  |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Pheochromocytoma Benign              |                                                                          |             
      Bilateral, Pheochromocytoma Benign   |                                                                          |             
 _____________________________________________________________________________________________________________________|             

                                                             Page   2                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 6| 6| 6| 7| 3| 7| 6| 7| 7| 7| 5| 7| 7| 7| 4| 7| 7| 7| 7| 7| 6| 6|             
                             DAY ON TEST   | 2| 2| 2| 7| 2| 4| 2| 9| 2| 8| 2| 2| 2| 9| 2| 2| 2| 9| 2| 2| 2| 2| 2| 3| 8|             
                                           | 9| 9| 2| 3| 2| 9| 9| 9| 9| 7| 9| 9| 9| 6| 9| 9| 9| 3| 9| 9| 9| 9| 9| 6| 1|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS FEMALE                 | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|             
    0 PPM                                  | 1| 1| 1| 1| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM - cont                   |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +|             
      Adenoma                              |                                                                          |             
      Fibrous Histiocytoma, Metastatic,    |                                                                          |             
           Mesentery                       |                                                       X                  |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                                                      X   |             
      Pars Distalis, Adenoma               |       X        X              X     X  X  X                             X|             
      Pars Distalis, Adenoma, Multiple     |                         X                                                |             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      C-Cell, Adenoma                      |                            X                                             |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Clitoral Gland                          | +  +  +  M  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenoma                              |             X                       X                                    |             
                                            __________________________________________________________________________|             
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Fibrous Histiocytoma, Metastatic,    |                                                                          |             
           Mesentery                       |                                                       X                  |             
                                            __________________________________________________________________________|             
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Polyp Stromal                        |                                                          X     X         |             
      Sarcoma Stromal                      |                                                    X                     |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node                              |                            +                       +  +              +   |             
      Iliac, Leukemia Mononuclear          |                                                                      X   |             
      Mediastinal, Fibrous Histiocytoma,   |                                                                          |             
           Metastatic, Mesentery           |                                                       X                  |             
      Mediastinal, Leukemia Mononuclear    |                            X                                         X   |             
      Renal, Leukemia Mononuclear          |                                                                      X   |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                            X                                         X   |             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Fibrous Histiocytoma, Metastatic,    |                                                                          |             
           Mesentery                       |                                                       X                  |             
      Leukemia Mononuclear                 |                            X                                         X   |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 | X                          X  X     X                    X           X   |             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                                                          |             
 _____________________________________________________________________________________________________________________|             

                                                             Page   3                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 6| 6| 6| 7| 3| 7| 6| 7| 7| 7| 5| 7| 7| 7| 4| 7| 7| 7| 7| 7| 6| 6|             
                             DAY ON TEST   | 2| 2| 2| 7| 2| 4| 2| 9| 2| 8| 2| 2| 2| 9| 2| 2| 2| 9| 2| 2| 2| 2| 2| 3| 8|             
                                           | 9| 9| 2| 3| 2| 9| 9| 9| 9| 7| 9| 9| 9| 6| 9| 9| 9| 3| 9| 9| 9| 9| 9| 6| 1|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS FEMALE                 | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|             
    0 PPM                                  | 1| 1| 1| 1| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |             
                                           |                                                                          |             
      Lymphoma Malignant                   |                                                                X         |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenoma                              |                                                                          |             
      Carcinoma                            |                                           X                              |             
      Fibroadenoma                         |       X  X        X                 X     X     X           X        X   |             
      Fibroadenoma, Multiple               |                         X  X  X        X                                 |             
      Sarcoma                              |                                                                          |             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Skeletal Muscle                         |                                                       +           +      |             
      Abdominal, Fibrous Histiocytoma,     |                                                                          |             
           Metastatic, Mesentery           |                                                       X                  |             
      Abdominal, Lipoma                    |                                                                   X      |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Astrocytoma Malignant                |                                        X                          X      |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Alveolar/Bronchiolar Adenoma         |                                                             X            |             
      Leukemia Mononuclear                 |                                                                      X   |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Harderian Gland                         |                                                             +            |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                                                      X   |             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SYSTEMIC LESIONS                          |                                                                          |             
                                            __________________________________________________________________________|             
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 | X                          X  X     X                    X           X   |             
      Lymphoma Malignant                   |                                                                X         |             
 _____________________________________________________________________________________________________________________|             

                                                             Page   4                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 6| 7| 7| 7| 5| 7| 7| 7| 7| 7| 7| 7| 7| 5| 6| 6| 6| 7| 7| 7|            |
                             DAY ON TEST   | 3| 3| 3| 3| 3| 9| 3| 3| 1| 8| 2| 2| 2| 2| 1| 3| 3| 3| 0| 6| 6| 7| 3| 3| 3|            |
                                           | 0| 0| 0| 0| 0| 6| 0| 0| 7| 8| 9| 9| 9| 9| 7| 0| 0| 0| 3| 1| 7| 1| 0| 0| 0|            |
 _____________________________________________________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   FISCHER 344 RATS FEMALE                 | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|     A      |
    0 PPM                                  | 4| 4| 4| 4| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 6|     L      |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|            |
 __________________________________________________________________________________________________________________________________ 
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Fibrous Histiocytoma, Metastatic,    |                                                                          |            |
           Mesentery                       |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Fibrous Histiocytoma, Metastatic,    |                                                                          |            |
           Mesentery                       |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Fibrous Histiocytoma, Metastatic,    |                                                                          |            |
           Mesentery                       |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Fibrous Histiocytoma, Metastatic,    |                                                                          |            |
           Mesentery                       |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Fibrous Histiocytoma, Metastatic,    |                                                                          |            |
           Mesentery                       |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Fibrous Histiocytoma, Metastatic,    |                                                                          |            |
           Mesentery                       |                                                                          |          1 |
      Hepatocellular Adenoma               |                                              X                           |          1 |
      Leukemia Mononuclear                 |          X        X                 X                       X  X         |         10 |
                                            __________________________________________________________________________|____________|
   Mesentery                               | +        +                             +     +                 +         |   9        |
      Fibrous Histiocytoma                 |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Oral Mucosa                             |                                                                          |   2        |
      Pharyngeal, Squamous Cell Carcinoma  |                                                                          |          2 |
                                            __________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Fibrous Histiocytoma, Metastatic,    |                                                                          |            |
           Mesentery                       |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Fibrous Histiocytoma, Metastatic,    |                                                                          |            |
           Mesentery                       |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
 __________________________________________________________________________________________________________________________________ 

                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  

                                                             Page   5                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 6| 7| 7| 7| 5| 7| 7| 7| 7| 7| 7| 7| 7| 5| 6| 6| 6| 7| 7| 7|            |
                             DAY ON TEST   | 3| 3| 3| 3| 3| 9| 3| 3| 1| 8| 2| 2| 2| 2| 1| 3| 3| 3| 0| 6| 6| 7| 3| 3| 3|            |
                                           | 0| 0| 0| 0| 0| 6| 0| 0| 7| 8| 9| 9| 9| 9| 7| 0| 0| 0| 3| 1| 7| 1| 0| 0| 0|            |
 _____________________________________________________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   FISCHER 344 RATS FEMALE                 | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|     A      |
    0 PPM                                  | 4| 4| 4| 4| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 6|     L      |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|            |
 __________________________________________________________________________________________________________________________________ 
 ENDOCRINE SYSTEM - cont                   |                                                                          |            |
                                           |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Pheochromocytoma Benign              |                                                    X                    X|          2 |
      Bilateral, Pheochromocytoma Benign   |                                                             X            |          1 |
                                            __________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Adenoma                              |                                                    X                     |          1 |
      Fibrous Histiocytoma, Metastatic,    |                                                                          |            |
           Mesentery                       |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
                                            __________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Leukemia Mononuclear                 |                                                                          |          1 |
      Pars Distalis, Adenoma               |       X           X  X  X  X              X  X  X        X           X   |         17 |
      Pars Distalis, Adenoma, Multiple     |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      C-Cell, Adenoma                      |                         X                       X                        |          3 |
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Clitoral Gland                          | +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  47        |
      Adenoma                              |                                                                          |          2 |
                                            __________________________________________________________________________|____________|
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Fibrous Histiocytoma, Metastatic,    |                                                                          |            |
           Mesentery                       |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Polyp Stromal                        |                   X                                                     X|          4 |
      Sarcoma Stromal                      |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                                             X            |          1 |
                                            __________________________________________________________________________|____________|
   Lymph Node                              |                                                    +        +  +         |   7        |
      Iliac, Leukemia Mononuclear          |                                                             X            |          2 |
      Mediastinal, Fibrous Histiocytoma,   |                                                                          |            |
           Metastatic, Mesentery           |                                                                          |          1 |
      Mediastinal, Leukemia Mononuclear    |                                                             X            |          3 |
      Renal, Leukemia Mononuclear          |                                                                          |          1 |
 __________________________________________________________________________________________________________________________________ 

                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  

                                                             Page   6                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 6| 7| 7| 7| 5| 7| 7| 7| 7| 7| 7| 7| 7| 5| 6| 6| 6| 7| 7| 7|            |
                             DAY ON TEST   | 3| 3| 3| 3| 3| 9| 3| 3| 1| 8| 2| 2| 2| 2| 1| 3| 3| 3| 0| 6| 6| 7| 3| 3| 3|            |
                                           | 0| 0| 0| 0| 0| 6| 0| 0| 7| 8| 9| 9| 9| 9| 7| 0| 0| 0| 3| 1| 7| 1| 0| 0| 0|            |
 _____________________________________________________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   FISCHER 344 RATS FEMALE                 | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|     A      |
    0 PPM                                  | 4| 4| 4| 4| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 6|     L      |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|            |
 __________________________________________________________________________________________________________________________________ 
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Leukemia Mononuclear                 |                                                             X            |          3 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +|  49        |
      Fibrous Histiocytoma, Metastatic,    |                                                                          |            |
           Mesentery                       |                                                                          |          1 |
      Leukemia Mononuclear                 |                   X                                                      |          3 |
                                            __________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |    X     X        X                 X                       X  X         |         12 |
                                            __________________________________________________________________________|____________|
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                                             X            |          1 |
      Lymphoma Malignant                   |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Adenoma                              |       X                 X                                                |          2 |
      Carcinoma                            |                                                                          |          1 |
      Fibroadenoma                         |       X  X  X     X                 X        X  X  X     X     X  X      |         19 |
      Fibroadenoma, Multiple               | X              X        X              X                                 |          8 |
      Sarcoma                              |                X                                                         |          1 |
                                            __________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Skeletal Muscle                         |                                                                          |   2        |
      Abdominal, Fibrous Histiocytoma,     |                                                                          |            |
           Metastatic, Mesentery           |                                                                          |          1 |
      Abdominal, Lipoma                    |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Astrocytoma Malignant                |                                                                          |          2 |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Alveolar/Bronchiolar Adenoma         |                                                                          |          1 |
      Leukemia Mononuclear                 |                                                             X            |          2 |
                                            __________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
 __________________________________________________________________________________________________________________________________ 

                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  

                                                             Page   7                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 6| 7| 7| 7| 5| 7| 7| 7| 7| 7| 7| 7| 7| 5| 6| 6| 6| 7| 7| 7|            |
                             DAY ON TEST   | 3| 3| 3| 3| 3| 9| 3| 3| 1| 8| 2| 2| 2| 2| 1| 3| 3| 3| 0| 6| 6| 7| 3| 3| 3|            |
                                           | 0| 0| 0| 0| 0| 6| 0| 0| 7| 8| 9| 9| 9| 9| 7| 0| 0| 0| 3| 1| 7| 1| 0| 0| 0|            |
 _____________________________________________________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   FISCHER 344 RATS FEMALE                 | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|     A      |
    0 PPM                                  | 4| 4| 4| 4| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 6|     L      |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|            |
 __________________________________________________________________________________________________________________________________ 
 SPECIAL SENSES SYSTEM - cont              |                                                                          |            |
                                           |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Harderian Gland                         |                                                                          |   1        |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 __________________________________________________________________________________________________________________________________ 
 SYSTEMIC LESIONS                          |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |    X     X        X                 X                       X  X         |         12 |
      Lymphoma Malignant                   |                                                                          |          1 |
 __________________________________________________________________________________________________________________________________ 

                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  

                                                             Page   8                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 5| 6| 7| 4| 7| 7| 7| 5| 7| 7| 7| 6| 7| 7|             
                             DAY ON TEST   | 2| 9| 2| 2| 2| 3| 2| 2| 1| 3| 2| 3| 5| 2| 8| 2| 2| 2| 4| 2| 3| 3| 1| 3| 3|             
                                           | 9| 5| 9| 9| 9| 0| 9| 9| 7| 0| 9| 3| 0| 9| 8| 9| 9| 9| 6| 9| 0| 0| 1| 0| 0|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS FEMALE                 | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|             
    100 PPM                                | 6| 6| 6| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 8| 8| 9|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Schwannoma Malignant, Metastatic,    |                                                                          |             
           Uterus                          |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |    X                                                                     |             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Carcinoma, Metastatic, Kidney        |                                     X                                    |             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Carcinoma, Metastatic, Pancreas      |                                                                   X      |             
      Carcinoma, Metastatic, Uterus        |                                           X                              |             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Carcinoma, Metastatic, Pancreas      |                                                                   X      |             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +|             
      Leukemia Mononuclear                 |    X                                                                     |             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Carcinoma, Metastatic, Kidney        |                                     X                                    |             
      Carcinoma, Metastatic, Pancreas      |                                                                   X      |             
      Carcinoma, Metastatic, Uterus        |                                           X                              |             
      Leukemia Mononuclear                 |    X  X     X     X     X                    X  X     X  X  X            |             
                                            __________________________________________________________________________|             
   Mesentery                               |    +              +        +              +     +              +         |             
      Carcinoma, Metastatic, Uterus        |                                           X                              |             
      Schwannoma Malignant, Metastatic,    |                                                                          |             
           Uterus                          |                                                                          |             
                                            __________________________________________________________________________|             
   Oral Mucosa                             |                                                       +                  |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Carcinoma                            |                                                       X           X      |             
      Carcinoma, Metastatic, Uterus        |                                           X                              |             
      Leukemia Mononuclear                 |    X        X                                                            |             
      Acinus, Adenoma                      |                                                                          |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Carcinoma, Metastatic, Uterus        |                                           X                              |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Carcinoma, Metastatic, Kidney        |                                     X                                    |             
      Leukemia Mononuclear                 |    X                                                                     |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Carcinoma, Metastatic, Kidney        |                                     X                                    |             
      Leukemia Mononuclear                 |                                                       X                  |             
 _____________________________________________________________________________________________________________________|             

                                                             Page   9                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 5| 6| 7| 4| 7| 7| 7| 5| 7| 7| 7| 6| 7| 7|             
                             DAY ON TEST   | 2| 9| 2| 2| 2| 3| 2| 2| 1| 3| 2| 3| 5| 2| 8| 2| 2| 2| 4| 2| 3| 3| 1| 3| 3|             
                                           | 9| 5| 9| 9| 9| 0| 9| 9| 7| 0| 9| 3| 0| 9| 8| 9| 9| 9| 6| 9| 0| 0| 1| 0| 0|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS FEMALE                 | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|             
    100 PPM                                | 6| 6| 6| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 8| 8| 9|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM - cont                   |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                                       X                  |             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                                       X                  |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |    X                                                     X               |             
      Pars Distalis, Adenoma               |          X     X              X                 X           X           X|             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Bilateral, C-Cell, Adenoma           |                                                                          |             
      C-Cell, Adenoma                      |    X                                                                    X|             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Clitoral Gland                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenoma                              | X                                            X                           |             
      Carcinoma                            |                                                                          |             
                                            __________________________________________________________________________|             
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Carcinoma, Metastatic, Kidney        |                                     X                                    |             
      Carcinoma, Metastatic, Pancreas      |                                                                   X      |             
      Leukemia Mononuclear                 |    X                                                     X               |             
                                            __________________________________________________________________________|             
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Carcinoma                            |                                           X                              |             
      Carcinoma, Metastatic, Pancreas      |                                                                   X      |             
      Polyp Stromal                        |       X              X                       X  X                        |             
      Schwannoma Malignant, Metastatic,    |                                                                          |             
           Uterus                          |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Carcinoma, Metastatic, Kidney        |                                     X                                    |             
      Leukemia Mononuclear                 |    X                                            X                        |             
                                            __________________________________________________________________________|             
   Lymph Node                              |    +        +           +           +                       +     +     +|             
      Mediastinal, Carcinoma, Metastatic,  |                                                                          |             
           Kidney                          |                                     X                                    |             
      Mediastinal, Carcinoma, Metastatic,  |                                                                          |             
           Pancreas                        |                                                                   X      |             
      Mediastinal, Leukemia Mononuclear    |    X        X           X                                                |             
      Pancreatic, Leukemia Mononuclear     |    X        X                                               X            |             
      Renal, Leukemia Mononuclear          |                                                             X            |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Carcinoma, Metastatic, Kidney        |                                     X                                    |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  10                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 5| 6| 7| 4| 7| 7| 7| 5| 7| 7| 7| 6| 7| 7|             
                             DAY ON TEST   | 2| 9| 2| 2| 2| 3| 2| 2| 1| 3| 2| 3| 5| 2| 8| 2| 2| 2| 4| 2| 3| 3| 1| 3| 3|             
                                           | 9| 5| 9| 9| 9| 0| 9| 9| 7| 0| 9| 3| 0| 9| 8| 9| 9| 9| 6| 9| 0| 0| 1| 0| 0|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS FEMALE                 | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|             
    100 PPM                                | 6| 6| 6| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 8| 8| 9|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |             
                                           |                                                                          |             
      Leukemia Mononuclear                 |    X  X     X                                X  X     X  X  X            |             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Carcinoma, Metastatic, Pancreas      |                                                                   X      |             
      Carcinoma, Metastatic, Uterus        |                                           X                              |             
      Leukemia Mononuclear                 |    X        X           X                    X  X        X               |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Carcinoma, Metastatic, Kidney        |                                     X                                    |             
      Carcinoma, Metastatic, Pancreas      |                                                                   X      |             
      Carcinoma, Metastatic, Uterus        |                                           X                              |             
      Leukemia Mononuclear                 |    X  X     X     X     X                    X  X        X  X            |             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Carcinoma, Metastatic, Kidney        |                                     X                                    |             
      Carcinoma, Metastatic, Pancreas      |                                                                   X      |             
      Leukemia Mononuclear                 |    X  X     X     X     X                       X                        |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenoma                              |                                                                          |             
      Carcinoma                            |                                     X                          X         |             
      Fibroadenoma                         | X  X        X  X        X                          X     X     X        X|             
      Fibroadenoma, Multiple               |                      X        X        X     X  X           X            |             
      Leukemia Mononuclear                 |    X                                                                     |             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Basal Cell Adenoma                   |                   X                                                      |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Skeletal Muscle                         |                                           +                              |             
      Carcinoma, Metastatic, Uterus        |                                           X                              |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |    X                    X                                                |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Alveolar/Bronchiolar Adenoma         |                                                                          |             
      Carcinoma, Metastatic, Kidney        |                                     X                                    |             
      Carcinoma, Metastatic, Pancreas      |                                                       X           X      |             
      Carcinoma, Metastatic, Uterus        |                                           X                              |             
      Leukemia Mononuclear                 |    X        X                                                            |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Pleura                                  |                                     +                                    |             
      Carcinoma, Metastatic, Kidney        |                                     X                                    |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  11                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 5| 6| 7| 4| 7| 7| 7| 5| 7| 7| 7| 6| 7| 7|             
                             DAY ON TEST   | 2| 9| 2| 2| 2| 3| 2| 2| 1| 3| 2| 3| 5| 2| 8| 2| 2| 2| 4| 2| 3| 3| 1| 3| 3|             
                                           | 9| 5| 9| 9| 9| 0| 9| 9| 7| 0| 9| 3| 0| 9| 8| 9| 9| 9| 6| 9| 0| 0| 1| 0| 0|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS FEMALE                 | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2|             
    100 PPM                                | 6| 6| 6| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 8| 8| 9|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM - cont                 |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Zymbal's Gland                          |                                  +                                       |             
      Carcinoma                            |                                  X                                       |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Carcinoma, Metastatic, Pancreas      |                                                                   X      |             
      Leukemia Mononuclear                 |    X                                                                     |             
      Transitional Epithelium, Carcinoma   |                                     X                                    |             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |    X                                                                     |             
 _____________________________________________________________________________________________________________________|             
 SYSTEMIC LESIONS                          |                                                                          |             
                                            __________________________________________________________________________|             
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |    X  X     X     X     X                    X  X     X  X  X            |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  12                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 6| 5| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 6|            |
                             DAY ON TEST   | 2| 2| 2| 2| 3| 2| 2| 2| 6| 7| 8| 2| 3| 2| 2| 2| 2| 2| 2| 2| 2| 4| 2| 2| 6|            |
                                           | 9| 9| 9| 9| 0| 9| 9| 9| 6| 0| 2| 9| 0| 9| 9| 9| 9| 9| 9| 9| 8| 2| 9| 9| 6|            |
 _____________________________________________________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   FISCHER 344 RATS FEMALE                 | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|     A      |
    100 PPM                                | 9| 9| 9| 9| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1|     L      |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|            |
 __________________________________________________________________________________________________________________________________ 
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Schwannoma Malignant, Metastatic,    |                                                                          |            |
           Uterus                          |                            X                                             |          1 |
                                            __________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Carcinoma, Metastatic, Kidney        |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Carcinoma, Metastatic, Pancreas      |                                                                          |          1 |
      Carcinoma, Metastatic, Uterus        |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Carcinoma, Metastatic, Pancreas      |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Leukemia Mononuclear                 |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Carcinoma, Metastatic, Kidney        |                                                                          |          1 |
      Carcinoma, Metastatic, Pancreas      |                                                                          |          1 |
      Carcinoma, Metastatic, Uterus        |                                                                          |          1 |
      Leukemia Mononuclear                 |    X                 X        X     X           X                        |         15 |
                                            __________________________________________________________________________|____________|
   Mesentery                               |             +              +                 +                 +        +|  11        |
      Carcinoma, Metastatic, Uterus        |                                                                          |          1 |
      Schwannoma Malignant, Metastatic,    |                                                                          |            |
           Uterus                          |                            X                                             |          1 |
                                            __________________________________________________________________________|____________|
   Oral Mucosa                             |                                                                          |   1        |
                                            __________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Carcinoma                            |                                                                          |          2 |
      Carcinoma, Metastatic, Uterus        |                                                                          |          1 |
      Leukemia Mononuclear                 |                                                                          |          2 |
      Acinus, Adenoma                      |          X                                                               |          1 |
                                            __________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Carcinoma, Metastatic, Uterus        |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Carcinoma, Metastatic, Kidney        |                                                                          |          1 |
      Leukemia Mononuclear                 |                                                                          |          1 |
 __________________________________________________________________________________________________________________________________ 

                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  

                                                             Page  13                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 6| 5| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 6|            |
                             DAY ON TEST   | 2| 2| 2| 2| 3| 2| 2| 2| 6| 7| 8| 2| 3| 2| 2| 2| 2| 2| 2| 2| 2| 4| 2| 2| 6|            |
                                           | 9| 9| 9| 9| 0| 9| 9| 9| 6| 0| 2| 9| 0| 9| 9| 9| 9| 9| 9| 9| 8| 2| 9| 9| 6|            |
 _____________________________________________________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   FISCHER 344 RATS FEMALE                 | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|     A      |
    100 PPM                                | 9| 9| 9| 9| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1|     L      |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|            |
 __________________________________________________________________________________________________________________________________ 
 CARDIOVASCULAR SYSTEM - cont              |                                                                          |            |
                                           |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Carcinoma, Metastatic, Kidney        |                                                                          |          1 |
      Leukemia Mononuclear                 |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                                                          |          2 |
      Pars Distalis, Adenoma               | X                       X                                   X  X     X  X|         12 |
                                            __________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Bilateral, C-Cell, Adenoma           |                                                                   X      |          1 |
      C-Cell, Adenoma                      |                                                                          |          2 |
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Clitoral Gland                          | +  +  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +|  48        |
      Adenoma                              |                   X                                                      |          3 |
      Carcinoma                            |                                                             X            |          1 |
                                            __________________________________________________________________________|____________|
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Carcinoma, Metastatic, Kidney        |                                                                          |          1 |
      Carcinoma, Metastatic, Pancreas      |                                                                          |          1 |
      Leukemia Mononuclear                 |                                                                          |          2 |
                                            __________________________________________________________________________|____________|
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Carcinoma                            |                                                                          |          1 |
      Carcinoma, Metastatic, Pancreas      |                                                                          |          1 |
      Polyp Stromal                        | X                                   X                             X      |          7 |
      Schwannoma Malignant, Metastatic,    |                                                                          |            |
           Uterus                          |                            X                                             |          1 |
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Carcinoma, Metastatic, Kidney        |                                                                          |          1 |
      Leukemia Mononuclear                 |                                                                          |          2 |
 __________________________________________________________________________________________________________________________________ 

                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  

                                                             Page  14                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 6| 5| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 6|            |
                             DAY ON TEST   | 2| 2| 2| 2| 3| 2| 2| 2| 6| 7| 8| 2| 3| 2| 2| 2| 2| 2| 2| 2| 2| 4| 2| 2| 6|            |
                                           | 9| 9| 9| 9| 0| 9| 9| 9| 6| 0| 2| 9| 0| 9| 9| 9| 9| 9| 9| 9| 8| 2| 9| 9| 6|            |
 _____________________________________________________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   FISCHER 344 RATS FEMALE                 | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|     A      |
    100 PPM                                | 9| 9| 9| 9| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1|     L      |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|            |
 __________________________________________________________________________________________________________________________________ 
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Lymph Node                              |                            +                       +                     |   9        |
      Mediastinal, Carcinoma, Metastatic,  |                                                                          |            |
           Kidney                          |                                                                          |          1 |
      Mediastinal, Carcinoma, Metastatic,  |                                                                          |            |
           Pancreas                        |                                                                          |          1 |
      Mediastinal, Leukemia Mononuclear    |                                                                          |          3 |
      Pancreatic, Leukemia Mononuclear     |                                                                          |          3 |
      Renal, Leukemia Mononuclear          |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Carcinoma, Metastatic, Kidney        |                                                                          |          1 |
      Leukemia Mononuclear                 |                               X                                          |          9 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Carcinoma, Metastatic, Pancreas      |                                                                          |          1 |
      Carcinoma, Metastatic, Uterus        |                                                                          |          1 |
      Leukemia Mononuclear                 |                               X                                          |          7 |
                                            __________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Carcinoma, Metastatic, Kidney        |                                                                          |          1 |
      Carcinoma, Metastatic, Pancreas      |                                                                          |          1 |
      Carcinoma, Metastatic, Uterus        |                                                                          |          1 |
      Leukemia Mononuclear                 |    X           X     X        X     X           X                        |         15 |
                                            __________________________________________________________________________|____________|
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Carcinoma, Metastatic, Kidney        |                                                                          |          1 |
      Carcinoma, Metastatic, Pancreas      |                                                                          |          1 |
      Leukemia Mononuclear                 |                               X                                          |          7 |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Adenoma                              |                                                             X            |          1 |
      Carcinoma                            |                                                                          |          2 |
      Fibroadenoma                         |          X  X           X     X                             X           X|         15 |
      Fibroadenoma, Multiple               |                   X  X                             X     X               |         10 |
      Leukemia Mononuclear                 |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Basal Cell Adenoma                   |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Skeletal Muscle                         |                                                                          |   1        |
      Carcinoma, Metastatic, Uterus        |                                                                          |          1 |
 __________________________________________________________________________________________________________________________________ 

                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  

                                                             Page  15                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 6| 5| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 6| 7| 7| 6|            |
                             DAY ON TEST   | 2| 2| 2| 2| 3| 2| 2| 2| 6| 7| 8| 2| 3| 2| 2| 2| 2| 2| 2| 2| 2| 4| 2| 2| 6|            |
                                           | 9| 9| 9| 9| 0| 9| 9| 9| 6| 0| 2| 9| 0| 9| 9| 9| 9| 9| 9| 9| 8| 2| 9| 9| 6|            |
 _____________________________________________________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   FISCHER 344 RATS FEMALE                 | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 2| 2| 2| 2| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|     A      |
    100 PPM                                | 9| 9| 9| 9| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1|     L      |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|            |
 __________________________________________________________________________________________________________________________________ 
 MUSCULOSKELETAL SYSTEM - cont             |                                                                          |            |
                                           |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                                                          |          2 |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Alveolar/Bronchiolar Adenoma         |                                        X                                 |          1 |
      Carcinoma, Metastatic, Kidney        |                                                                          |          1 |
      Carcinoma, Metastatic, Pancreas      |                                                                          |          2 |
      Carcinoma, Metastatic, Uterus        |                                                                          |          1 |
      Leukemia Mononuclear                 |                                                                          |          2 |
                                            __________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Pleura                                  |                                                                          |   1        |
      Carcinoma, Metastatic, Kidney        |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Zymbal's Gland                          |                                                                          |   1        |
      Carcinoma                            |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Carcinoma, Metastatic, Pancreas      |                                                                          |          1 |
      Leukemia Mononuclear                 |                                                                          |          1 |
      Transitional Epithelium, Carcinoma   |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                                                          |          1 |
 __________________________________________________________________________________________________________________________________ 
 SYSTEMIC LESIONS                          |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |    X           X     X        X     X           X                        |         16 |
 __________________________________________________________________________________________________________________________________ 

                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  

                                                             Page  16                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 5| 7| 7| 7| 7| 7| 7| 7| 7| 7| 5| 7| 7| 7| 7| 7| 7| 6| 7| 7| 6| 7| 4| 7|             
                             DAY ON TEST   | 2| 7| 0| 2| 0| 2| 2| 2| 2| 2| 2| 4| 2| 2| 2| 2| 2| 2| 6| 2| 2| 8| 2| 9| 1|             
                                           | 1| 3| 7| 9| 3| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 5| 9| 9| 7| 9| 6| 8|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS FEMALE                 | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
    200 PPM                                | 1| 1| 1| 1| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hepatocellular Adenoma               |                                                                          |             
      Leukemia Mononuclear                 | X  X        X     X              X  X        X        X              X  X|             
                                            __________________________________________________________________________|             
   Mesentery                               |                                  +        +                 +        +   |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                                                      X  X|             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                                                         X|             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Tongue                                  |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                                                         X|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                                                      X  X|             
      Pheochromocytoma Benign              |                                                                          |             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenoma                              |                X                                                         |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                                                         X|             
      Pars Distalis, Adenoma               | X        X  X     X  X  X                 X                    X         |             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      C-Cell, Adenoma                      |       X                                                                  |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Clitoral Gland                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Carcinoma                            |                                                                          |             
      Bilateral, Adenoma                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  17                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 5| 7| 7| 7| 7| 7| 7| 7| 7| 7| 5| 7| 7| 7| 7| 7| 7| 6| 7| 7| 6| 7| 4| 7|             
                             DAY ON TEST   | 2| 7| 0| 2| 0| 2| 2| 2| 2| 2| 2| 4| 2| 2| 2| 2| 2| 2| 6| 2| 2| 8| 2| 9| 1|             
                                           | 1| 3| 7| 9| 3| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 5| 9| 9| 7| 9| 6| 8|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS FEMALE                 | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
    200 PPM                                | 1| 1| 1| 1| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Granulosa-Theca Tumor Malignant      |                                                                          |             
                                            __________________________________________________________________________|             
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Polyp Stromal                        | X     X                             X     X        X           X         |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |             X                    X                                   X  X|             
                                            __________________________________________________________________________|             
   Lymph Node                              |    +                             +                                   +  +|             
      Bronchial, Leukemia Mononuclear      |                                                                         X|             
      Deep Cervical, Leukemia Mononuclear  |                                                                      X   |             
      Iliac, Leukemia Mononuclear          |                                  X                                   X   |             
      Mediastinal, Leukemia Mononuclear    |                                  X                                   X  X|             
      Pancreatic, Leukemia Mononuclear     |                                  X                                   X  X|             
      Renal, Leukemia Mononuclear          |    X                             X                                   X  X|             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                  X                    X              X  X|             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                  X                                   X  X|             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 | X  X        X     X  X           X  X     X  X        X           X  X  X|             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                  X  X                                X  X|             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenoma                              |       X                                                                  |             
      Carcinoma                            |                                                                          |             
      Fibroadenoma                         |          X        X        X  X              X     X        X            |             
      Fibroadenoma, Multiple               |       X              X                                                   |             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                                       X              X   |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Alveolar/Bronchiolar Adenoma         |                                                                          |             
      Carcinoma, Metastatic, Mammary Gland |                                                                          |             
      Leukemia Mononuclear                 |                                  X                                   X  X|             
 _____________________________________________________________________________________________________________________|             

                                                             Page  18                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 5| 7| 7| 7| 7| 7| 7| 7| 7| 7| 5| 7| 7| 7| 7| 7| 7| 6| 7| 7| 6| 7| 4| 7|             
                             DAY ON TEST   | 2| 7| 0| 2| 0| 2| 2| 2| 2| 2| 2| 4| 2| 2| 2| 2| 2| 2| 6| 2| 2| 8| 2| 9| 1|             
                                           | 1| 3| 7| 9| 3| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 5| 9| 9| 7| 9| 6| 8|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS FEMALE                 | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
    200 PPM                                | 1| 1| 1| 1| 2| 2| 2| 2| 2| 2| 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM - cont                 |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Eye                                     |                                                             +            |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                                                      X   |             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                                                         X|             
 _____________________________________________________________________________________________________________________|             
 SYSTEMIC LESIONS                          |                                                                          |             
                                            __________________________________________________________________________|             
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 | X  X        X     X  X           X  X     X  X        X           X  X  X|             
 _____________________________________________________________________________________________________________________|             

                                                             Page  19                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 6| 7| 5| 7| 7| 6| 7| 5| 6| 7| 6| 6| 7| 5| 7| 7| 7| 5| 7| 7|            |
                             DAY ON TEST   | 2| 2| 2| 2| 0| 9| 2| 2| 2| 1| 0| 2| 6| 2| 2| 7| 9| 2| 8| 2| 2| 0| 8| 2| 2|            |
                                           | 9| 9| 9| 9| 7| 8| 9| 1| 9| 1| 5| 9| 1| 4| 9| 1| 9| 9| 0| 9| 9| 0| 6| 9| 9|            |
 _____________________________________________________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   FISCHER 344 RATS FEMALE                 | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|     A      |
    200 PPM                                | 4| 4| 4| 4| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 6|     L      |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|            |
 __________________________________________________________________________________________________________________________________ 
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hepatocellular Adenoma               |                                                                         X|          1 |
      Leukemia Mononuclear                 |    X           X     X  X  X  X                 X     X           X      |         19 |
                                            __________________________________________________________________________|____________|
   Mesentery                               |                +                                      +  +               |   7        |
                                            __________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |    X                                                                     |          3 |
                                            __________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Tongue                                  |                                                             +            |   1        |
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                                                          |          2 |
      Pheochromocytoma Benign              |          X                                                               |          1 |
                                            __________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Adenoma                              |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Parathyroid Gland                       | +  +  M  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
                                            __________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                                                          |          1 |
      Pars Distalis, Adenoma               | X                 X              X        X  X  X  X     X  X           X|         18 |
                                            __________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      C-Cell, Adenoma                      |       X                                                                  |          2 |
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |                                                                          |            |
    None                                   |                                                                          |            |
 __________________________________________________________________________________________________________________________________ 

                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  

                                                             Page  20                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 6| 7| 5| 7| 7| 6| 7| 5| 6| 7| 6| 6| 7| 5| 7| 7| 7| 5| 7| 7|            |
                             DAY ON TEST   | 2| 2| 2| 2| 0| 9| 2| 2| 2| 1| 0| 2| 6| 2| 2| 7| 9| 2| 8| 2| 2| 0| 8| 2| 2|            |
                                           | 9| 9| 9| 9| 7| 8| 9| 1| 9| 1| 5| 9| 1| 4| 9| 1| 9| 9| 0| 9| 9| 0| 6| 9| 9|            |
 _____________________________________________________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   FISCHER 344 RATS FEMALE                 | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|     A      |
    200 PPM                                | 4| 4| 4| 4| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 6|     L      |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|            |
 __________________________________________________________________________________________________________________________________ 
 GENITAL SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Clitoral Gland                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Carcinoma                            |             X                                                            |          1 |
      Bilateral, Adenoma                   |                                                                      X   |          1 |
                                            __________________________________________________________________________|____________|
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Granulosa-Theca Tumor Malignant      |                                                 X                        |          1 |
                                            __________________________________________________________________________|____________|
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Polyp Stromal                        |                   X                       X        X                     |          9 |
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |    X                    X                             X                  |          7 |
                                            __________________________________________________________________________|____________|
   Lymph Node                              |    +  +  +     +        +  +  +     +  +        +     +                  |  15        |
      Bronchial, Leukemia Mononuclear      |                                                                          |          1 |
      Deep Cervical, Leukemia Mononuclear  |                                                                          |          1 |
      Iliac, Leukemia Mononuclear          |    X                                            X                        |          4 |
      Mediastinal, Leukemia Mononuclear    |    X           X           X                          X                  |          7 |
      Pancreatic, Leukemia Mononuclear     |    X           X        X                                                |          6 |
      Renal, Leukemia Mononuclear          |    X                                                                     |          5 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |    X           X     X  X                             X                  |          9 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |    X           X     X  X                             X                  |          8 |
                                            __________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |    X           X     X  X  X  X                 X     X           X      |         22 |
                                            __________________________________________________________________________|____________|
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |    X           X        X  X                    X                        |          9 |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Adenoma                              |                                                                          |          1 |
      Carcinoma                            |                                                 X                        |          1 |
      Fibroadenoma                         |          X        X        X     X           X        X                 X|         14 |
      Fibroadenoma, Multiple               |    X           X        X                 X                              |          6 |
                                            __________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
 __________________________________________________________________________________________________________________________________ 

                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  

                                                             Page  21                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 6| 7| 5| 7| 7| 6| 7| 5| 6| 7| 6| 6| 7| 5| 7| 7| 7| 5| 7| 7|            |
                             DAY ON TEST   | 2| 2| 2| 2| 0| 9| 2| 2| 2| 1| 0| 2| 6| 2| 2| 7| 9| 2| 8| 2| 2| 0| 8| 2| 2|            |
                                           | 9| 9| 9| 9| 7| 8| 9| 1| 9| 1| 5| 9| 1| 4| 9| 1| 9| 9| 0| 9| 9| 0| 6| 9| 9|            |
 _____________________________________________________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   FISCHER 344 RATS FEMALE                 | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|     A      |
    200 PPM                                | 4| 4| 4| 4| 4| 4| 4| 4| 4| 5| 5| 5| 5| 5| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 6|     L      |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|            |
 __________________________________________________________________________________________________________________________________ 
 NERVOUS SYSTEM - cont                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                                                          |          2 |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Alveolar/Bronchiolar Adenoma         |                                                                X         |          1 |
      Carcinoma, Metastatic, Mammary Gland |                                                 X                        |          1 |
      Leukemia Mononuclear                 |    X           X     X     X                                             |          7 |
                                            __________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Eye                                     |                                                                          |   1        |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |    X                                                                     |          2 |
                                            __________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                                                          |          1 |
 __________________________________________________________________________________________________________________________________ 
 SYSTEMIC LESIONS                          |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |    X           X     X  X  X  X                 X     X           X      |         22 |
 __________________________________________________________________________________________________________________________________ 

                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  

                                                             Page  22                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 5| 6| 6| 7| 7| 5| 7| 4| 7| 7| 7| 5| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 2| 1| 1| 7| 2| 2| 0| 2| 5| 3| 2| 2| 8| 2| 2| 0| 0| 2| 2| 2| 2| 2| 2| 2| 1|             
                                           | 9| 1| 6| 3| 9| 9| 3| 9| 7| 0| 9| 9| 9| 9| 9| 5| 8| 9| 9| 9| 9| 9| 9| 9| 1|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS FEMALE                 | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
    400 PPM                                | 6| 6| 6| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 8| 8| 9|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |             X                                                            |             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |    X        X        X        X     X        X  X           X           X|             
                                            __________________________________________________________________________|             
   Mesentery                               |             +                    +           +                 +  +     +|             
      Leukemia Mononuclear                 |             X                                                            |             
                                            __________________________________________________________________________|             
   Oral Mucosa                             |                                           +                       +      |             
      Pharyngeal, Squamous Cell Papilloma  |                                                                   X      |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                                                          |             
      Acinus, Adenoma                      |                                                                          |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                                                          |             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                                                          |             
                                            __________________________________________________________________________|             
   Tongue                                  |                                                                          |             
      Squamous Cell Papilloma              |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                                                         X|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                              X                           |             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +     +  +|             
      Leukemia Mononuclear                 |                                              X                          X|             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                                                          |             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                                                         X|             
      Pars Distalis, Adenoma               | X        X                       X        X        X  X        X  X      |             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  23                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 5| 6| 6| 7| 7| 5| 7| 4| 7| 7| 7| 5| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 2| 1| 1| 7| 2| 2| 0| 2| 5| 3| 2| 2| 8| 2| 2| 0| 0| 2| 2| 2| 2| 2| 2| 2| 1|             
                                           | 9| 1| 6| 3| 9| 9| 3| 9| 7| 0| 9| 9| 9| 9| 9| 5| 8| 9| 9| 9| 9| 9| 9| 9| 1|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS FEMALE                 | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
    400 PPM                                | 6| 6| 6| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 8| 8| 9|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Clitoral Gland                          | +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenoma                              |                                                                          |             
      Carcinoma                            |                                                          X               |             
                                            __________________________________________________________________________|             
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                                                          |             
                                            __________________________________________________________________________|             
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                                                          |             
      Polyp Stromal                        |                   X                                      X  X        X   |             
      Polyp Stromal, Multiple              |                                              X                           |             
                                            __________________________________________________________________________|             
   Vagina                                  |                                                                          |             
      Lipoma                               |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |    X                                                                     |             
                                            __________________________________________________________________________|             
   Lymph Node                              |    +     +  +                                +  +        +              +|             
      Axillary, Leukemia Mononuclear       |                                                                          |             
      Iliac, Leukemia Mononuclear          |             X                                X                           |             
      Mediastinal, Leukemia Mononuclear    |    X        X                                   X                       X|             
      Pancreatic, Leukemia Mononuclear     |             X                                                            |             
      Renal, Leukemia Mononuclear          |    X        X                                X  X                        |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |             X                                X                           |             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |    X        X                                X  X                       X|             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |    X        X                 X     X        X  X           X           X|             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |    X        X                                X  X                       X|             
      Lymphoma Malignant                   |                                                                   X      |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Carcinoma                            |                                                    X                     |             
      Fibroadenoma                         |             X        X        X  X  X     X           X     X  X     X   |             
      Fibroadenoma, Multiple               |                                                                          |             
      Leukemia Mononuclear                 |                                                                          |             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Keratoacanthoma                      |                            X                                             |             
      Trichoepithelioma                    |                                                                X         |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  24                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 5| 6| 6| 7| 7| 5| 7| 4| 7| 7| 7| 5| 7| 7| 7| 6| 7| 7| 7| 7| 7| 7| 7| 7|             
                             DAY ON TEST   | 2| 1| 1| 7| 2| 2| 0| 2| 5| 3| 2| 2| 8| 2| 2| 0| 0| 2| 2| 2| 2| 2| 2| 2| 1|             
                                           | 9| 1| 6| 3| 9| 9| 3| 9| 7| 0| 9| 9| 9| 9| 9| 5| 8| 9| 9| 9| 9| 9| 9| 9| 1|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS FEMALE                 | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3|             
    400 PPM                                | 6| 6| 6| 6| 7| 7| 7| 7| 7| 7| 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 8| 8| 9|             
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                              X                          X|             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Alveolar/Bronchiolar Adenoma         |                                                                          |             
      Carcinoma, Metastatic, Clitoral Gland|                                                          X               |             
      Leukemia Mononuclear                 |             X                                   X                       X|             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                                                          |             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Eye                                     |                                        +  +                              |             
                                            __________________________________________________________________________|             
   Zymbal's Gland                          |                                                                          |             
      Carcinoma                            |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                                                         X|             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 SYSTEMIC LESIONS                          |                                                                          |             
                                            __________________________________________________________________________|             
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |    X        X        X        X     X        X  X           X           X|             
      Lymphoma Malignant                   |                                                                   X      |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  25                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 7| 6| 3| 7| 6| 6| 6| 6| 7| 6| 6| 6| 5| 6| 7| 7| 7| 6| 7| 7| 7| 5| 6| 7|            |
                             DAY ON TEST   | 7| 2| 3| 8| 2| 0| 4| 2| 2| 2| 0| 8| 3| 8| 9| 2| 2| 2| 4| 2| 2| 2| 8| 3| 2|            |
                                           | 2| 9| 9| 0| 9| 3| 9| 5| 8| 9| 5| 7| 4| 3| 2| 9| 9| 9| 1| 9| 9| 9| 4| 6| 9|            |
 _____________________________________________________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   FISCHER 344 RATS FEMALE                 | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4|     A      |
    400 PPM                                | 9| 9| 9| 9| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1|     L      |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|            |
 __________________________________________________________________________________________________________________________________ 
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                               X                                          |          1 |
                                            __________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                               X        X                             X   |          4 |
                                            __________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 | X     X  X     X     X  X     X  X  X  X  X           X  X           X   |         23 |
                                            __________________________________________________________________________|____________|
   Mesentery                               |          +        +     +                       +     +           +      |  12        |
      Leukemia Mononuclear                 |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Oral Mucosa                             |                                                                          |   2        |
      Pharyngeal, Squamous Cell Papilloma  |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                         X     X                                          |          2 |
      Acinus, Adenoma                      |                                                    X                     |          1 |
                                            __________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                               X                                          |          1 |
                                            __________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                         X     X                                          |          2 |
                                            __________________________________________________________________________|____________|
   Tongue                                  |                +                                   +                     |   2        |
      Squamous Cell Papilloma              |                X                                                         |          1 |
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |          X     X              X                                          |          4 |
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                               X                                          |          2 |
                                            __________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Leukemia Mononuclear                 |       X  X              X     X                                          |          6 |
                                            __________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                               X                                          |          1 |
                                            __________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 __________________________________________________________________________________________________________________________________ 

                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  

                                                             Page  26                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 7| 6| 3| 7| 6| 6| 6| 6| 7| 6| 6| 6| 5| 6| 7| 7| 7| 6| 7| 7| 7| 5| 6| 7|            |
                             DAY ON TEST   | 7| 2| 3| 8| 2| 0| 4| 2| 2| 2| 0| 8| 3| 8| 9| 2| 2| 2| 4| 2| 2| 2| 8| 3| 2|            |
                                           | 2| 9| 9| 0| 9| 3| 9| 5| 8| 9| 5| 7| 4| 3| 2| 9| 9| 9| 1| 9| 9| 9| 4| 6| 9|            |
 _____________________________________________________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   FISCHER 344 RATS FEMALE                 | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4|     A      |
    400 PPM                                | 9| 9| 9| 9| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1|     L      |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|            |
 __________________________________________________________________________________________________________________________________ 
 ENDOCRINE SYSTEM - cont                   |                                                                          |            |
                                           |                                                                          |            |
      Leukemia Mononuclear                 |                         X     X     X                                    |          4 |
      Pars Distalis, Adenoma               | X           X     X              X  X           X           X            |         15 |
                                            __________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Clitoral Gland                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Adenoma                              |                                                    X                     |          1 |
      Carcinoma                            |                                                 X                        |          2 |
                                            __________________________________________________________________________|____________|
   Ovary                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                               X                                      X   |          2 |
                                            __________________________________________________________________________|____________|
   Uterus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                         X     X                                          |          2 |
      Polyp Stromal                        |             X                       X        X                           |          7 |
      Polyp Stromal, Multiple              |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Vagina                                  |                      +                                                   |   1        |
      Lipoma                               |                      X                                                   |          1 |
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                X        X     X                                      X   |          5 |
                                            __________________________________________________________________________|____________|
   Lymph Node                              | +     +  +     +        +     +  +  +  +        +        +           +   |  19        |
      Axillary, Leukemia Mononuclear       |                         X                                            X   |          2 |
      Iliac, Leukemia Mononuclear          |                X              X                                          |          4 |
      Mediastinal, Leukemia Mononuclear    |       X  X     X        X     X  X     X                             X   |         12 |
      Pancreatic, Leukemia Mononuclear     |                X        X     X                                      X   |          5 |
      Renal, Leukemia Mononuclear          |       X  X     X              X  X                                   X   |         10 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                X        X     X        X                             X   |          7 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |       X  X              X     X     X  X                             X   |         12 |
                                            __________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |       X  X     X     X  X     X  X  X  X  X           X  X           X   |         21 |
                                            __________________________________________________________________________|____________|
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |          X     X              X        X                             X   |         10 |
      Lymphoma Malignant                   |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
 __________________________________________________________________________________________________________________________________ 

                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  

                                                             Page  27                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 7| 6| 3| 7| 6| 6| 6| 6| 7| 6| 6| 6| 5| 6| 7| 7| 7| 6| 7| 7| 7| 5| 6| 7|            |
                             DAY ON TEST   | 7| 2| 3| 8| 2| 0| 4| 2| 2| 2| 0| 8| 3| 8| 9| 2| 2| 2| 4| 2| 2| 2| 8| 3| 2|            |
                                           | 2| 9| 9| 0| 9| 3| 9| 5| 8| 9| 5| 7| 4| 3| 2| 9| 9| 9| 1| 9| 9| 9| 4| 6| 9|            |
 _____________________________________________________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   FISCHER 344 RATS FEMALE                 | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4|     A      |
    400 PPM                                | 9| 9| 9| 9| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1|     L      |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|            |
 __________________________________________________________________________________________________________________________________ 
 INTEGUMENTARY SYSTEM - cont               |                                                                          |            |
                                           |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Carcinoma                            |                                                                          |          1 |
      Fibroadenoma                         | X           X                 X           X        X     X  X           X|         18 |
      Fibroadenoma, Multiple               |                      X     X                                             |          2 |
      Leukemia Mononuclear                 | X                             X                                          |          2 |
                                            __________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Keratoacanthoma                      |                                                                          |          1 |
      Trichoepithelioma                    |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |          X     X              X  X                                       |          6 |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Alveolar/Bronchiolar Adenoma         |                      X                                         X         |          2 |
      Carcinoma, Metastatic, Clitoral Gland|                                                                          |          1 |
      Leukemia Mononuclear                 |          X     X              X                                      X   |          7 |
                                            __________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |          X     X              X                       X                  |          4 |
                                            __________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                               X                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Eye                                     |                                                                          |   2        |
                                            __________________________________________________________________________|____________|
   Zymbal's Gland                          |                                                                         +|   1        |
      Carcinoma                            |                                                                         X|          1 |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |          X     X              X                                      X   |          5 |
                                            __________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                               X                                          |          1 |
 __________________________________________________________________________________________________________________________________ 
 SYSTEMIC LESIONS                          |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 __________________________________________________________________________________________________________________________________ 

                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  

                                                             Page  28                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 6| 7| 6| 3| 7| 6| 6| 6| 6| 7| 6| 6| 6| 5| 6| 7| 7| 7| 6| 7| 7| 7| 5| 6| 7|            |
                             DAY ON TEST   | 7| 2| 3| 8| 2| 0| 4| 2| 2| 2| 0| 8| 3| 8| 9| 2| 2| 2| 4| 2| 2| 2| 8| 3| 2|            |
                                           | 2| 9| 9| 0| 9| 3| 9| 5| 8| 9| 5| 7| 4| 3| 2| 9| 9| 9| 1| 9| 9| 9| 4| 6| 9|            |
 _____________________________________________________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   FISCHER 344 RATS FEMALE                 | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4|     A      |
    400 PPM                                | 9| 9| 9| 9| 9| 9| 9| 9| 9| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1|     L      |
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|            |
 __________________________________________________________________________________________________________________________________ 
 SYSTEMIC LESIONS - cont                   |                                                                          |            |
                                           |                                                                          |            |
      Leukemia Mononuclear                 | X     X  X     X     X  X     X  X  X  X  X           X  X           X   |         23 |
      Lymphoma Malignant                   |                                                                          |          1 |
 __________________________________________________________________________________________________________________________________ 

                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  

                                                             Page  29                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 6| 6| 7| 6| 7| 7| 6| 7| 7| 6| 5| 3| 7| 7| 5| 7| 7| 7| 6| 7| 7| 7| 4| 7| 3|             
                             DAY ON TEST   | 9| 9| 1| 4| 1| 2| 0| 2| 2| 0| 9| 8| 1| 2| 7| 1| 2| 2| 6| 2| 2| 0| 7| 2| 0|             
                                           | 5| 2| 9| 0| 8| 2| 4| 2| 2| 2| 5| 8| 9| 2| 9| 8| 2| 2| 7| 2| 2| 1| 3| 2| 9|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
    0 PPM                                  | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |       X                                                                  |             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Carcinoma                            |                                                       X                  |             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |       X  X                                                               |             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hepatocellular Adenoma               |             X                                                            |             
      Histiocytic Sarcoma                  |                                                                          |             
      Leukemia Mononuclear                 |       X  X  X  X  X     X  X  X           X  X  X  X        X  X  X     X|             
                                            __________________________________________________________________________|             
   Mesentery                               |    +  +        +  +     +           +                             +  +   |             
      Leukemia Mononuclear                 |                         X                                                |             
      Schwannoma Benign                    |                                     X                                    |             
                                            __________________________________________________________________________|             
   Oral Mucosa                             |                            +                                             |             
      Pharyngeal, Squamous Cell Papilloma  |                            X                                             |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |       X     X     X                       X  X                 X         |             
      Acinus, Adenoma                      |                                                                      X   |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |       X                                                                  |             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |       X                                                                  |             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |       X           X        X                                             |             
                                            __________________________________________________________________________|             
   Tooth                                   |                                                 +           +            |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |       X           X        X                 X                           |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                           X  X                 X         |             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                X  X                                            X         |             
      Pheochromocytoma Benign              | X           X                                      X           X         |             
      Bilateral, Pheochromocytoma Benign   |                                              X              X            |             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenoma                              |             X                                               X            |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  30                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 6| 6| 7| 6| 7| 7| 6| 7| 7| 6| 5| 3| 7| 7| 5| 7| 7| 7| 6| 7| 7| 7| 4| 7| 3|             
                             DAY ON TEST   | 9| 9| 1| 4| 1| 2| 0| 2| 2| 0| 9| 8| 1| 2| 7| 1| 2| 2| 6| 2| 2| 0| 7| 2| 0|             
                                           | 5| 2| 9| 0| 8| 2| 4| 2| 2| 2| 5| 8| 9| 2| 9| 8| 2| 2| 7| 2| 2| 1| 3| 2| 9|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
    0 PPM                                  | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM - cont                   |                                                                          |             
                                           |                                                                          |             
      Leukemia Mononuclear                 |                   X                                                      |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |       X                                                                  |             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |       X                                                                  |             
      Pars Distalis, Adenoma               | X  X                    X     X        X                    X        X   |             
      Pars Intermedia, Adenoma             |                                                                          |             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |       X                 X                                                |             
      C-Cell, Adenoma                      |                      X                          X                        |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |       X                                                                  |             
      Mesothelioma Benign                  |                                                                          |             
                                            __________________________________________________________________________|             
   Penis                                   |                                                                          |             
                                            __________________________________________________________________________|             
   Preputial Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenoma                              |                   X                                                      |             
      Carcinoma                            |                                  X                                       |             
      Leukemia Mononuclear                 |       X                                                                  |             
                                            __________________________________________________________________________|             
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |       X           X                                                      |             
                                            __________________________________________________________________________|             
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |       X                 X                                                |             
                                            __________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Bilateral, Interstitial Cell, Adenoma|       X  X  X  X  X  X     X        X  X  X  X  X  X  X  X     X     X   |             
      Interstitial Cell, Adenoma           | X  X                    X                                         X      |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                                                                          |             
      Leukemia Mononuclear                 |       X  X  X              X                 X              X           X|             
                                            __________________________________________________________________________|             
   Lymph Node                              | +     +  +  +     +     +  +                 +              +     +     +|             
      Axillary, Leukemia Mononuclear       |                                                                          |             
      Deep Cervical, Leukemia Mononuclear  |             X                                                            |             
      Iliac, Leukemia Mononuclear          |                            X                                             |             
      Mediastinal, Leukemia Mononuclear    |             X     X     X  X                                      X     X|             
      Pancreatic, Leukemia Mononuclear     |       X  X  X     X     X                    X                           |             
      Renal, Leukemia Mononuclear          |       X                                                     X            |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |       X     X     X     X  X              X  X              X  X  X     X|             
 _____________________________________________________________________________________________________________________|             

                                                             Page  31                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 6| 6| 7| 6| 7| 7| 6| 7| 7| 6| 5| 3| 7| 7| 5| 7| 7| 7| 6| 7| 7| 7| 4| 7| 3|             
                             DAY ON TEST   | 9| 9| 1| 4| 1| 2| 0| 2| 2| 0| 9| 8| 1| 2| 7| 1| 2| 2| 6| 2| 2| 0| 7| 2| 0|             
                                           | 5| 2| 9| 0| 8| 2| 4| 2| 2| 2| 5| 8| 9| 2| 9| 8| 2| 2| 7| 2| 2| 1| 3| 2| 9|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
    0 PPM                                  | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |       X     X  X  X     X  X              X  X              X     X     X|             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  A  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |       X  X  X  X  X  X  X  X              X  X  X  X        X  X  X     X|             
      Mesothelioma Malignant               |                                                                          |             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |       X     X     X        X                 X                 X        X|             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +|             
      Fibroadenoma                         |             X                                                            |             
      Leukemia Mononuclear                 |       X  X        X     X                                                |             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Keratoacanthoma                      |                      X                                      X            |             
      Leukemia Mononuclear                 |                                                                          |             
      Squamous Cell Papilloma              |                                                             X            |             
      Subcutaneous Tissue, Fibroma         |                                                       X                  |             
      Subcutaneous Tissue, Lipoma          |                                     X                                    |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |       X     X     X     X                 X  X                    X     X|             
                                            __________________________________________________________________________|             
   Spinal Cord                             |                                              +                           |             
      Nerve, Leukemia Mononuclear          |                                              X                           |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Alveolar/Bronchiolar Adenoma         |                                                                          |             
      Leukemia Mononuclear                 |       X     X     X     X                 X  X              X           X|             
      Osteosarcoma, Metastatic, Nose       |                                                                          |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |       X                                   X                             X|             
      Osteosarcoma                         |                                                                          |             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |       X                                                                  |             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Zymbal's Gland                          |          +                                                               |             
      Carcinoma                            |          X                                                               |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  32                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 6| 6| 7| 6| 7| 7| 6| 7| 7| 6| 5| 3| 7| 7| 5| 7| 7| 7| 6| 7| 7| 7| 4| 7| 3|             
                             DAY ON TEST   | 9| 9| 1| 4| 1| 2| 0| 2| 2| 0| 9| 8| 1| 2| 7| 1| 2| 2| 6| 2| 2| 0| 7| 2| 0|             
                                           | 5| 2| 9| 0| 8| 2| 4| 2| 2| 2| 5| 8| 9| 2| 9| 8| 2| 2| 7| 2| 2| 1| 3| 2| 9|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
    0 PPM                                  | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM - cont                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |       X     X     X     X                 X  X                 X         |             
      Renal Tubule, Adenoma                |                         X                                                |             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |       X                                                     X            |             
 _____________________________________________________________________________________________________________________|             
 SYSTEMIC LESIONS                          |                                                                          |             
                                            __________________________________________________________________________|             
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Histiocytic Sarcoma                  |                                                                          |             
      Leukemia Mononuclear                 |       X  X  X  X  X  X  X  X  X           X  X  X  X        X  X  X     X|             
      Mesothelioma Benign                  |                                                                          |             
      Mesothelioma Malignant               |                                                                          |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  33                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 3| 7| 6| 7| 6| 7| 7| 5| 7| 6| 6| 4| 7| 7| 5| 7| 7|            |
                             DAY ON TEST   | 2| 2| 2| 2| 2| 2| 2| 2| 8| 2| 2| 2| 4| 2| 2| 7| 2| 5| 6| 3| 2| 2| 7| 1| 2|            |
                                           | 2| 2| 2| 2| 2| 2| 2| 2| 8| 2| 5| 2| 4| 2| 2| 1| 2| 6| 7| 4| 2| 2| 4| 5| 2|            |
 _____________________________________________________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     A      |
    0 PPM                                  | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 __________________________________________________________________________________________________________________________________ 
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                                       X              X   |          2 |
                                            __________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Leukemia Mononuclear                 |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Carcinoma                            |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                                                          |          2 |
                                            __________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hepatocellular Adenoma               |                                                                          |          1 |
      Histiocytic Sarcoma                  |                                                             X            |          1 |
      Leukemia Mononuclear                 |          X  X     X  X        X        X     X     X  X        X     X  X|         28 |
                                            __________________________________________________________________________|____________|
   Mesentery                               |                         +                                +              +|  11        |
      Leukemia Mononuclear                 |                                                                          |          1 |
      Schwannoma Benign                    |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Oral Mucosa                             |                                                                          |   1        |
      Pharyngeal, Squamous Cell Papilloma  |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                                       X                  |          7 |
      Acinus, Adenoma                      |                                        X                                 |          2 |
                                            __________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                                       X                  |          2 |
                                            __________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                                    X  X                  |          3 |
                                            __________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                                       X                  |          4 |
                                            __________________________________________________________________________|____________|
   Tooth                                   |                                                                          |   2        |
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                                       X                  |          5 |
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                                    X                     |          4 |
                                            __________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 __________________________________________________________________________________________________________________________________ 

                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  

                                                             Page  34                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 3| 7| 6| 7| 6| 7| 7| 5| 7| 6| 6| 4| 7| 7| 5| 7| 7|            |
                             DAY ON TEST   | 2| 2| 2| 2| 2| 2| 2| 2| 8| 2| 2| 2| 4| 2| 2| 7| 2| 5| 6| 3| 2| 2| 7| 1| 2|            |
                                           | 2| 2| 2| 2| 2| 2| 2| 2| 8| 2| 5| 2| 4| 2| 2| 1| 2| 6| 7| 4| 2| 2| 4| 5| 2|            |
 _____________________________________________________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     A      |
    0 PPM                                  | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 __________________________________________________________________________________________________________________________________ 
 ENDOCRINE SYSTEM - cont                   |                                                                          |            |
                                           |                                                                          |            |
      Leukemia Mononuclear                 |                                                                      X   |          4 |
      Pheochromocytoma Benign              | X              X                       X     X              X  X        X|         11 |
      Bilateral, Pheochromocytoma Benign   |                      X           X        X           X                  |          6 |
                                            __________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Adenoma                              |                               X                       X                  |          4 |
      Leukemia Mononuclear                 |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                                       X              X   |          3 |
      Pars Distalis, Adenoma               | X     X           X  X              X        X           X  X        X   |         16 |
      Pars Intermedia, Adenoma             |                               X                                          |          1 |
                                            __________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                                                          |          2 |
      C-Cell, Adenoma                      |                                                                          |          2 |
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +|  49        |
      Leukemia Mononuclear                 |                                                                          |          1 |
      Mesothelioma Benign                  |                            X                                             |          1 |
                                            __________________________________________________________________________|____________|
   Penis                                   |    +                                                                     |   1        |
                                            __________________________________________________________________________|____________|
   Preputial Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Adenoma                              | X                    X                                                   |          3 |
      Carcinoma                            |                X                          X                    X        X|          5 |
      Leukemia Mononuclear                 |                                                       X                  |          2 |
                                            __________________________________________________________________________|____________|
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                                       X                  |          3 |
                                            __________________________________________________________________________|____________|
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                                       X                  |          3 |
                                            __________________________________________________________________________|____________|
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +|  49        |
      Bilateral, Interstitial Cell, Adenoma|    X     X  X  X  X  X     X  X  X     X  X     X  X  X        X        X|         33 |
      Interstitial Cell, Adenoma           | X     X                             X        X                    X      |          9 |
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Histiocytic Sarcoma                  |                                                             X            |          1 |
 __________________________________________________________________________________________________________________________________ 

                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  

                                                             Page  35                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 3| 7| 6| 7| 6| 7| 7| 5| 7| 6| 6| 4| 7| 7| 5| 7| 7|            |
                             DAY ON TEST   | 2| 2| 2| 2| 2| 2| 2| 2| 8| 2| 2| 2| 4| 2| 2| 7| 2| 5| 6| 3| 2| 2| 7| 1| 2|            |
                                           | 2| 2| 2| 2| 2| 2| 2| 2| 8| 2| 5| 2| 4| 2| 2| 1| 2| 6| 7| 4| 2| 2| 4| 5| 2|            |
 _____________________________________________________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     A      |
    0 PPM                                  | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 __________________________________________________________________________________________________________________________________ 
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |            |
                                           |                                                                          |            |
      Leukemia Mononuclear                 |                               X              X     X  X              X   |         12 |
                                            __________________________________________________________________________|____________|
   Lymph Node                              |             +     +           +              +     +  +        +  +  +   |  20        |
      Axillary, Leukemia Mononuclear       |                                                       X              X   |          2 |
      Deep Cervical, Leukemia Mononuclear  |                                                       X              X   |          3 |
      Iliac, Leukemia Mononuclear          |                                                       X              X   |          3 |
      Mediastinal, Leukemia Mononuclear    |             X                                X                       X   |          9 |
      Pancreatic, Leukemia Mononuclear     |             X                                      X  X                  |          9 |
      Renal, Leukemia Mononuclear          |             X     X           X                    X  X              X   |          8 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |             X     X  X        X                       X              X   |         17 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |             X                 X        X           X  X              X   |         17 |
                                            __________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Leukemia Mononuclear                 |          X  X     X  X        X        X     X     X  X        X     X  X|         28 |
      Mesothelioma Malignant               |             X                                                            |          1 |
                                            __________________________________________________________________________|____________|
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |             X                 X                       X              X   |         11 |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Fibroadenoma                         |       X        X  X                                                      |          4 |
      Leukemia Mononuclear                 |                                                       X                  |          5 |
                                            __________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Keratoacanthoma                      |       X           X                                X           X         |          6 |
      Leukemia Mononuclear                 |                                                       X                  |          1 |
      Squamous Cell Papilloma              |       X                          X     X                                 |          4 |
      Subcutaneous Tissue, Fibroma         | X  X                          X                                          |          4 |
      Subcutaneous Tissue, Lipoma          |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                                    X                     |          9 |
                                            __________________________________________________________________________|____________|
   Spinal Cord                             |                                                                          |   1        |
      Nerve, Leukemia Mononuclear          |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |                                                                          |            |
 __________________________________________________________________________________________________________________________________ 

                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  

                                                             Page  36                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 7| 7| 7| 7| 7| 3| 7| 6| 7| 6| 7| 7| 5| 7| 6| 6| 4| 7| 7| 5| 7| 7|            |
                             DAY ON TEST   | 2| 2| 2| 2| 2| 2| 2| 2| 8| 2| 2| 2| 4| 2| 2| 7| 2| 5| 6| 3| 2| 2| 7| 1| 2|            |
                                           | 2| 2| 2| 2| 2| 2| 2| 2| 8| 2| 5| 2| 4| 2| 2| 1| 2| 6| 7| 4| 2| 2| 4| 5| 2|            |
 _____________________________________________________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     A      |
    0 PPM                                  | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 __________________________________________________________________________________________________________________________________ 
 RESPIRATORY SYSTEM - cont                 |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Alveolar/Bronchiolar Adenoma         |                   X                                                      |          1 |
      Leukemia Mononuclear                 |             X                                X        X              X   |         12 |
      Osteosarcoma, Metastatic, Nose       |                               X                                          |          1 |
                                            __________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                                    X                 X   |          5 |
      Osteosarcoma                         |                               X                                          |          1 |
                                            __________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Zymbal's Gland                          |                                                                          |   1        |
      Carcinoma                            |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |             X                                         X              X   |         10 |
      Renal Tubule, Adenoma                |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                                       X                  |          3 |
 __________________________________________________________________________________________________________________________________ 
 SYSTEMIC LESIONS                          |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Histiocytic Sarcoma                  |                                                             X            |          1 |
      Leukemia Mononuclear                 |          X  X     X  X        X        X     X     X  X        X     X  X|         29 |
      Mesothelioma Benign                  |                            X                                             |          1 |
      Mesothelioma Malignant               |             X                                                            |          1 |
 __________________________________________________________________________________________________________________________________ 

                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  

                                                             Page  37                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 6| 6| 7| 7| 4| 7| 7| 6| 6| 7| 6| 7| 7| 7| 6| 6| 7| 5| 7| 6| 6| 6| 6| 7|             
                             DAY ON TEST   | 2| 6| 4| 2| 2| 6| 2| 2| 9| 6| 2| 4| 2| 2| 2| 8| 6| 2| 9| 0| 2| 0| 6| 6| 1|             
                                           | 2| 6| 1| 2| 2| 6| 2| 2| 8| 5| 2| 2| 2| 2| 2| 2| 6| 2| 8| 0| 8| 7| 6| 5| 8|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
    100 PPM                                | 5| 5| 5| 5| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 7|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                                                          |             
      Mesothelioma Malignant               |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                                                         X|             
      Mesothelioma Malignant               |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Mesothelioma Malignant               |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Mesothelioma Malignant               |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 | X              X     X                                                   |             
      Mesothelioma Malignant               |                                                                          |             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hepatocellular Adenoma               | X                                                                        |             
      Leukemia Mononuclear                 | X  X  X  X  X  X  X  X  X  X  X  X     X  X           X  X  X  X  X  X  X|             
      Mesothelioma Malignant               |                                                                          |             
                                            __________________________________________________________________________|             
   Mesentery                               | +                 +     +  +                       +     +        +      |             
      Leukemia Mononuclear                 | X                                                                        |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 | X                                                     X                 X|             
      Mesothelioma Malignant               |                                                                          |             
      Acinus, Adenoma                      |                                                                          |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                                                          |             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Mesothelioma Malignant               |                                                                          |             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                                                          |             
      Mesothelioma Malignant               |                                                                          |             
                                            __________________________________________________________________________|             
   Tooth                                   |                               +                                          |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 | X                                                                        |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Carcinoma                            |                                           X                              |             
      Leukemia Mononuclear                 | X     X                                                     X            |             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 | X     X                          X                                       |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  38                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 6| 6| 7| 7| 4| 7| 7| 6| 6| 7| 6| 7| 7| 7| 6| 6| 7| 5| 7| 6| 6| 6| 6| 7|             
                             DAY ON TEST   | 2| 6| 4| 2| 2| 6| 2| 2| 9| 6| 2| 4| 2| 2| 2| 8| 6| 2| 9| 0| 2| 0| 6| 6| 1|             
                                           | 2| 6| 1| 2| 2| 6| 2| 2| 8| 5| 2| 2| 2| 2| 2| 2| 6| 2| 8| 0| 8| 7| 6| 5| 8|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
    100 PPM                                | 5| 5| 5| 5| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 7|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM - cont                   |                                                                          |             
                                           |                                                                          |             
      Pheochromocytoma Benign              |                                                             X            |             
      Bilateral, Pheochromocytoma Benign   |                                                                          |             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenoma                              |          X        X                                                      |             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                                                          |             
      Pars Distalis, Adenoma               |             X        X     X        X  X     X  X           X            |             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Bilateral, C-Cell, Adenoma           |                                                                          |             
      C-Cell, Carcinoma                    |                                                 X                        |             
      Follicular Cell, Adenoma             |                                        X                                 |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                                       X                  |             
      Mesothelioma Malignant               |                                                                          |             
                                            __________________________________________________________________________|             
   Preputial Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Carcinoma                            |                   X                 X                                    |             
                                            __________________________________________________________________________|             
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 | X                                                     X                  |             
      Mesothelioma Malignant               |                                                                          |             
                                            __________________________________________________________________________|             
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                                       X                  |             
      Mesothelioma Malignant               |                                                                          |             
                                            __________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Mesothelioma Malignant               |                                                                          |             
      Bilateral, Interstitial Cell, Adenoma| X  X  X  X     X  X     X  X  X     X  X  X  X  X  X  X  X  X  X        X|             
      Interstitial Cell, Adenoma           |             X                    X                                X      |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |    X  X     X                 X                       X           X  X  X|             
                                            __________________________________________________________________________|             
   Lymph Node                              | +  +        +  +  +           +  +     +              +  +  +  +  +     +|             
      Axillary, Leukemia Mononuclear       |                                                                          |             
      Iliac, Leukemia Mononuclear          |                               X                       X                  |             
      Mediastinal, Leukemia Mononuclear    | X           X  X  X           X                       X        X         |             
      Pancreatic, Leukemia Mononuclear     | X                                      X              X  X              X|             
      Renal, Leukemia Mononuclear          |                               X                       X     X     X      |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 | X           X  X  X                                   X  X  X     X  X   |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  39                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 6| 6| 7| 7| 4| 7| 7| 6| 6| 7| 6| 7| 7| 7| 6| 6| 7| 5| 7| 6| 6| 6| 6| 7|             
                             DAY ON TEST   | 2| 6| 4| 2| 2| 6| 2| 2| 9| 6| 2| 4| 2| 2| 2| 8| 6| 2| 9| 0| 2| 0| 6| 6| 1|             
                                           | 2| 6| 1| 2| 2| 6| 2| 2| 8| 5| 2| 2| 2| 2| 2| 2| 6| 2| 8| 0| 8| 7| 6| 5| 8|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
    100 PPM                                | 5| 5| 5| 5| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 7|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 | X     X     X  X     X                                X  X  X     X  X   |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 | X  X  X  X  X  X  X  X  X  X  X  X     X  X           X  X  X  X  X  X  X|             
      Mesothelioma Malignant               |                                                                          |             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 | X     X  X  X  X                 X                    X  X  X  X         |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Carcinoma                            |                                           X                              |             
      Fibroadenoma                         | X                                                                        |             
      Leukemia Mononuclear                 |             X                                                            |             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Keratoacanthoma                      |                                           X                             X|             
      Mesothelioma Malignant               |                                                                          |             
      Squamous Cell Papilloma              |                                     X                                    |             
      Trichoepithelioma                    |                                                                          |             
      Subcutaneous Tissue, Fibroma         |                                              X                           |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Skeletal Muscle                         |                                                                          |             
      Mesothelioma Malignant               |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |       X                 X                             X     X     X      |             
      Oligodendroglioma Malignant          |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Carcinoma, Metastatic, Mammary Gland |                                           X                              |             
      Carcinoma, Metastatic, Zymbal's Gland|                                                                          |             
      Leukemia Mononuclear                 | X     X     X  X              X                             X            |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 | X     X                                                                  |             
      Respiratory Epithelium, Squamous     |                                                                          |             
          Cell Carcinoma                   |                                                                          |             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Eye                                     |                                                                          |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  40                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 6| 6| 7| 7| 4| 7| 7| 6| 6| 7| 6| 7| 7| 7| 6| 6| 7| 5| 7| 6| 6| 6| 6| 7|             
                             DAY ON TEST   | 2| 6| 4| 2| 2| 6| 2| 2| 9| 6| 2| 4| 2| 2| 2| 8| 6| 2| 9| 0| 2| 0| 6| 6| 1|             
                                           | 2| 6| 1| 2| 2| 6| 2| 2| 8| 5| 2| 2| 2| 2| 2| 2| 6| 2| 8| 0| 8| 7| 6| 5| 8|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
    100 PPM                                | 5| 5| 5| 5| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 7|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM - cont              |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Zymbal's Gland                          |                                                                          |             
      Carcinoma                            |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                X                                      X  X  X            |             
      Mesenchymal Tumor Malignant          |                                                                          |             
      Renal Tubule, Carcinoma              |                                                                          |             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                                       X                  |             
      Mesothelioma Malignant               |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 SYSTEMIC LESIONS                          |                                                                          |             
                                            __________________________________________________________________________|             
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 | X  X  X  X  X  X  X  X  X  X  X  X     X  X           X  X  X  X  X  X  X|             
      Mesothelioma Malignant               |                                                                          |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  41                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 5| 7| 6| 7| 6| 7| 7| 7| 7| 7| 6| 7| 6| 6| 6| 7| 7| 4| 6| 6| 7| 5| 4| 6|            |
                             DAY ON TEST   | 2| 3| 2| 0| 2| 0| 0| 0| 2| 2| 2| 1| 2| 2| 6| 6| 2| 2| 4| 7| 7| 2| 5| 5| 2|            |
                                           | 2| 8| 2| 4| 2| 4| 8| 1| 2| 2| 2| 8| 2| 5| 7| 4| 2| 2| 4| 7| 3| 2| 3| 5| 0|            |
 _____________________________________________________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 1|     A      |
    100 PPM                                | 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 8| 8| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 0|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 __________________________________________________________________________________________________________________________________ 
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  +  +|  48        |
      Leukemia Mononuclear                 |                                           X                              |          1 |
      Mesothelioma Malignant               |                                                       X                  |          1 |
                                            __________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  +  +|  48        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  M  +  +  +  +  +|  47        |
      Leukemia Mononuclear                 |                                                                          |          1 |
      Mesothelioma Malignant               |                                                       X                  |          1 |
                                            __________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  M  +  +  +  +  +|  47        |
      Mesothelioma Malignant               |                                                       X                  |          1 |
                                            __________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  M  +  +  +  +  +|  47        |
      Mesothelioma Malignant               |                                                       X                  |          1 |
                                            __________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  M  +  +  +  +  +|  47        |
      Leukemia Mononuclear                 |                                           X        X                     |          5 |
      Mesothelioma Malignant               |                                                       X                  |          1 |
                                            __________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +|  49        |
      Hepatocellular Adenoma               |                                                                          |          1 |
      Leukemia Mononuclear                 |    X     X     X                       X  X     X  X        X     X     X|         31 |
      Mesothelioma Malignant               |                                                       X                  |          1 |
                                            __________________________________________________________________________|____________|
   Mesentery                               | +        +     +              +        +           +        +            |  14        |
      Leukemia Mononuclear                 |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  +  +  +  +  +  +|  48        |
      Leukemia Mononuclear                 |          X     X                                            X     X      |          7 |
      Mesothelioma Malignant               |                                                       X                  |          1 |
      Acinus, Adenoma                      |                                                                X         |          1 |
                                            __________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                                                   X      |          1 |
                                            __________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +|  49        |
      Mesothelioma Malignant               |                                                       X                  |          1 |
                                            __________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +|  49        |
      Leukemia Mononuclear                 |                                           X                              |          1 |
      Mesothelioma Malignant               |                                                       X                  |          1 |
                                            __________________________________________________________________________|____________|
   Tooth                                   |                                                                          |   1        |
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |    X           X                                   X              X     X|          6 |
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |                                                                          |            |
 __________________________________________________________________________________________________________________________________ 

                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  

                                                             Page  42                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 5| 7| 6| 7| 6| 7| 7| 7| 7| 7| 6| 7| 6| 6| 6| 7| 7| 4| 6| 6| 7| 5| 4| 6|            |
                             DAY ON TEST   | 2| 3| 2| 0| 2| 0| 0| 0| 2| 2| 2| 1| 2| 2| 6| 6| 2| 2| 4| 7| 7| 2| 5| 5| 2|            |
                                           | 2| 8| 2| 4| 2| 4| 8| 1| 2| 2| 2| 8| 2| 5| 7| 4| 2| 2| 4| 7| 3| 2| 3| 5| 0|            |
 _____________________________________________________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 1|     A      |
    100 PPM                                | 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 8| 8| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 0|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 __________________________________________________________________________________________________________________________________ 
 ENDOCRINE SYSTEM - cont                   |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +|  49        |
      Carcinoma                            |                                                                          |          1 |
      Leukemia Mononuclear                 |                                                                          |          3 |
                                            __________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +|  49        |
      Leukemia Mononuclear                 |                                                    X                     |          4 |
      Pheochromocytoma Benign              |                   X                                                      |          2 |
      Bilateral, Pheochromocytoma Benign   |                                                                X         |          1 |
                                            __________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  +  +  +  +  +  +|  48        |
      Adenoma                              |                                                                          |          2 |
                                            __________________________________________________________________________|____________|
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                X                                                  X     X|          3 |
      Pars Distalis, Adenoma               |       X                    X  X           X                 X            |         13 |
                                            __________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Bilateral, C-Cell, Adenoma           |                         X                                                |          1 |
      C-Cell, Carcinoma                    |                                                                          |          1 |
      Follicular Cell, Adenoma             |       X                                                                  |          2 |
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +|  49        |
      Leukemia Mononuclear                 |                                                                          |          1 |
      Mesothelioma Malignant               |                                                       X                  |          1 |
                                            __________________________________________________________________________|____________|
   Preputial Gland                         | +  +  +  +  +  +  +  +  M  +  +  M  +  +  +  +  +  +  +  M  +  +  +  +  +|  47        |
      Carcinoma                            |                                                                          |          2 |
                                            __________________________________________________________________________|____________|
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  +  +|  48        |
      Leukemia Mononuclear                 |                X                                                  X     X|          5 |
      Mesothelioma Malignant               |                                                       X                  |          1 |
                                            __________________________________________________________________________|____________|
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  M  +  +  +  +  +|  47        |
      Leukemia Mononuclear                 |                                                                   X      |          2 |
      Mesothelioma Malignant               |                                                       X                  |          1 |
                                            __________________________________________________________________________|____________|
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +|  49        |
      Mesothelioma Malignant               |                                                       X                  |          1 |
      Bilateral, Interstitial Cell, Adenoma| X  X  X  X  X  X  X  X  X     X     X           X     X        X        X|         35 |
      Interstitial Cell, Adenoma           |                            X     X        X  X                       X   |          8 |
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
 __________________________________________________________________________________________________________________________________ 

                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  

                                                             Page  43                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 5| 7| 6| 7| 6| 7| 7| 7| 7| 7| 6| 7| 6| 6| 6| 7| 7| 4| 6| 6| 7| 5| 4| 6|            |
                             DAY ON TEST   | 2| 3| 2| 0| 2| 0| 0| 0| 2| 2| 2| 1| 2| 2| 6| 6| 2| 2| 4| 7| 7| 2| 5| 5| 2|            |
                                           | 2| 8| 2| 4| 2| 4| 8| 1| 2| 2| 2| 8| 2| 5| 7| 4| 2| 2| 4| 7| 3| 2| 3| 5| 0|            |
 _____________________________________________________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 1|     A      |
    100 PPM                                | 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 8| 8| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 0|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 __________________________________________________________________________________________________________________________________ 
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |    X     X     X                          X                       X      |         13 |
                                            __________________________________________________________________________|____________|
   Lymph Node                              |    +     +     +     +  +              +  +        +        +     +     +|  25        |
      Axillary, Leukemia Mononuclear       |                                                             X            |          1 |
      Iliac, Leukemia Mononuclear          |                                        X                    X     X      |          5 |
      Mediastinal, Leukemia Mononuclear    |    X     X     X                       X  X                       X     X|         14 |
      Pancreatic, Leukemia Mononuclear     |          X     X                          X                             X|          9 |
      Renal, Leukemia Mononuclear          |                X                       X  X        X              X     X|         10 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |    X           X                          X     X  X        X     X     X|         17 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  M  +  +  +  +  +|  47        |
      Leukemia Mononuclear                 |    X           X                          X     X  X                    X|         16 |
                                            __________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  +  +  +  +  +  +|  48        |
      Leukemia Mononuclear                 |    X     X     X                    X  X  X     X  X        X     X     X|         32 |
      Mesothelioma Malignant               |                                                       X                  |          1 |
                                            __________________________________________________________________________|____________|
   Thymus                                  | +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Leukemia Mononuclear                 |    X     X     X                                   X                    X|         15 |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +|  48        |
      Carcinoma                            |                                                                          |          1 |
      Fibroadenoma                         |                   X                 X                                    |          3 |
      Leukemia Mononuclear                 |                X                                                         |          2 |
                                            __________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Keratoacanthoma                      |                                                 X           X            |          4 |
      Mesothelioma Malignant               |                                                       X                  |          1 |
      Squamous Cell Papilloma              |                                                                          |          1 |
      Trichoepithelioma                    |             X                                                            |          1 |
      Subcutaneous Tissue, Fibroma         |                                                                   X      |          2 |
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Skeletal Muscle                         |                                                       +                  |   1        |
      Mesothelioma Malignant               |                                                       X                  |          1 |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                                                   X      |          6 |
      Oligodendroglioma Malignant          |                                                                      X   |          1 |
 __________________________________________________________________________________________________________________________________ 

                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  

                                                             Page  44                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 5| 7| 6| 7| 6| 7| 7| 7| 7| 7| 6| 7| 6| 6| 6| 7| 7| 4| 6| 6| 7| 5| 4| 6|            |
                             DAY ON TEST   | 2| 3| 2| 0| 2| 0| 0| 0| 2| 2| 2| 1| 2| 2| 6| 6| 2| 2| 4| 7| 7| 2| 5| 5| 2|            |
                                           | 2| 8| 2| 4| 2| 4| 8| 1| 2| 2| 2| 8| 2| 5| 7| 4| 2| 2| 4| 7| 3| 2| 3| 5| 0|            |
 _____________________________________________________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 1|     A      |
    100 PPM                                | 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 8| 8| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 0|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 __________________________________________________________________________________________________________________________________ 
 NERVOUS SYSTEM - cont                     |                                                                          |            |
                                           |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Carcinoma, Metastatic, Mammary Gland |                                                                          |          1 |
      Carcinoma, Metastatic, Zymbal's Gland|                      X                                                   |          1 |
      Leukemia Mononuclear                 |    X           X                                            X     X     X|         11 |
                                            __________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                X                                                         |          3 |
      Respiratory Epithelium, Squamous     |                                                                          |            |
          Cell Carcinoma                   |                   X                                                      |          1 |
                                            __________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                                                   X      |          1 |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Eye                                     |                               +                                          |   1        |
                                            __________________________________________________________________________|____________|
   Zymbal's Gland                          |                      +                                                   |   1        |
      Carcinoma                            |                      X                                                   |          1 |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  +  +  +  +  +  +|  48        |
      Leukemia Mononuclear                 |                                           X        X              X     X|          8 |
      Mesenchymal Tumor Malignant          |                               X                                          |          1 |
      Renal Tubule, Carcinoma              |             X                                                            |          1 |
                                            __________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  M  +  +  +  M  +  +  +  +  +|  47        |
      Leukemia Mononuclear                 |    X                                                              X     X|          4 |
      Mesothelioma Malignant               |                                                       X                  |          1 |
 __________________________________________________________________________________________________________________________________ 
 SYSTEMIC LESIONS                          |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |    X     X     X                    X  X  X     X  X        X     X     X|         32 |
      Mesothelioma Malignant               |                                                       X                  |          1 |
 __________________________________________________________________________________________________________________________________ 

                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  

                                                             Page  45                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 5| 7| 7| 7| 5| 6| 7| 7| 7| 5| 7| 5| 6| 2| 7| 7| 6| 7| 7| 5| 7| 7|             
                             DAY ON TEST   | 2| 2| 2| 8| 2| 2| 2| 9| 4| 2| 2| 2| 8| 0| 2| 7| 6| 0| 2| 6| 0| 2| 3| 2| 2|             
                                           | 2| 2| 2| 9| 2| 2| 2| 6| 4| 2| 2| 2| 0| 8| 5| 9| 9| 0| 2| 9| 0| 2| 4| 2| 2|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|             
    200 PPM                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Lipoma                               |                                                                          |             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |          X                                                               |             
      Lipoma                               | X                                                                        |             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |          X           X                                                   |             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Hepatocellular Carcinoma             |                                                                          |             
      Leukemia Mononuclear                 |          X     X     X  X  X  X     X              X     X              X|             
                                            __________________________________________________________________________|             
   Mesentery                               | +                 +              +           +                           |             
                                            __________________________________________________________________________|             
   Oral Mucosa                             |                                                                          |             
      Pharyngeal, Squamous Cell Papilloma  |                                                                          |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |          X           X  X                                                |             
      Acinus, Adenoma                      |                                                                          |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                                                          |             
      Squamous Cell Papilloma              |                                           X                              |             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Tooth                                   |       +                                                                  |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                      X                                                   |             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                     X                    X              X|             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                         X           X              X     X               |             
      Pheochromocytoma Benign              |                            X                 X        X                 X|             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenoma                              |                                                                         X|             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                                          X               |             
      Pars Distalis, Adenoma               |       X                                   X     X     X     X     X  X  X|             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             

                                                             Page  46                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 5| 7| 7| 7| 5| 6| 7| 7| 7| 5| 7| 5| 6| 2| 7| 7| 6| 7| 7| 5| 7| 7|             
                             DAY ON TEST   | 2| 2| 2| 8| 2| 2| 2| 9| 4| 2| 2| 2| 8| 0| 2| 7| 6| 0| 2| 6| 0| 2| 3| 2| 2|             
                                           | 2| 2| 2| 9| 2| 2| 2| 6| 4| 2| 2| 2| 0| 8| 5| 9| 9| 0| 2| 9| 0| 2| 4| 2| 2|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|             
    200 PPM                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM - cont                   |                                                                          |             
                                           |                                                                          |             
      C-Cell, Adenoma                      |    X                                                                     |             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Mesothelioma Benign                  |                                                                          |             
                                            __________________________________________________________________________|             
   Preputial Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenoma                              | X        X        X                                   X           X     X|             
      Leukemia Mononuclear                 |          X                                                               |             
                                            __________________________________________________________________________|             
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |          X                          X                                    |             
                                            __________________________________________________________________________|             
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                      X                                                   |             
                                            __________________________________________________________________________|             
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Bilateral, Interstitial Cell, Adenoma| X  X        X  X     X  X  X  X  X     X     X     X  X  X  X  X     X  X|             
      Interstitial Cell, Adenoma           |          X        X                 X                                    |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                X              X     X              X     X              X|             
      Melanoma Malignant, Metastatic, Skin |                                                                          |             
                                            __________________________________________________________________________|             
   Lymph Node                              |          +           +  +     +     +  +           +     +        +     +|             
      Axillary, Leukemia Mononuclear       |                         X                                                |             
      Deep Cervical, Leukemia Mononuclear  |          X                                                               |             
      Iliac, Leukemia Mononuclear          |          X           X  X     X                    X     X               |             
      Mediastinal, Leukemia Mononuclear    |          X           X  X     X     X                    X               |             
      Pancreatic, Leukemia Mononuclear     |          X           X  X     X     X              X                     |             
      Renal, Leukemia Mononuclear          |          X           X  X     X     X              X     X               |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |          X     X     X  X     X     X              X     X              X|             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |          X     X     X  X           X              X     X               |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |          X     X     X  X  X        X              X     X              X|             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |          X           X  X           X              X     X               |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Fibroadenoma                         |                                                                          |             
      Leukemia Mononuclear                 |          X           X                                                   |             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             

                                                             Page  47                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 7| 7| 7| 5| 7| 7| 7| 5| 6| 7| 7| 7| 5| 7| 5| 6| 2| 7| 7| 6| 7| 7| 5| 7| 7|             
                             DAY ON TEST   | 2| 2| 2| 8| 2| 2| 2| 9| 4| 2| 2| 2| 8| 0| 2| 7| 6| 0| 2| 6| 0| 2| 3| 2| 2|             
                                           | 2| 2| 2| 9| 2| 2| 2| 6| 4| 2| 2| 2| 0| 8| 5| 9| 9| 0| 2| 9| 0| 2| 4| 2| 2|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|             
    200 PPM                                | 0| 0| 0| 0| 0| 0| 0| 0| 0| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2| 2| 2| 2| 2| 2|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM - cont               |                                                                          |             
                                           |                                                                          |             
      Keratoacanthoma                      |                   X                                                      |             
      Keratoacanthoma, Multiple            |                                        X                                 |             
      Squamous Cell Papilloma              |                                                                          |             
      Pinna, Melanoma Malignant            |                                                                          |             
      Subcutaneous Tissue, Fibroma         |       X                             X                    X               |             
      Subcutaneous Tissue, Lipoma          |                                                                   X      |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +     +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                      X              X              X     X               |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Alveolar/Bronchiolar Carcinoma       |                                                                X     X   |             
      Leukemia Mononuclear                 |          X     X     X  X           X                    X               |             
      Melanoma Malignant, Metastatic, Skin |                                                                          |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +     +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                      X                                                   |             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Zymbal's Gland                          |                                                                          |             
      Carcinoma                            |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |          X           X              X                                    |             
      Renal Tubule, Adenoma                |                                                                          |             
      Renal Tubule, Adenoma, Multiple      |                                        X                                 |             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                                    X     X               |             
 _____________________________________________________________________________________________________________________|             
 SYSTEMIC LESIONS                          |                                                                          |             
                                            __________________________________________________________________________|             
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |          X     X     X  X  X  X     X              X     X              X|             
      Mesothelioma Benign                  |                                                                          |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  48                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 6| 6| 6| 7| 5| 6| 7| 7| 7| 4| 7| 7| 7| 6| 7| 7| 7| 6| 5| 6| 5| 6|            |
                             DAY ON TEST   | 2| 2| 2| 6| 4| 4| 2| 8| 4| 2| 2| 1| 8| 2| 2| 2| 3| 2| 2| 2| 0| 3| 7| 2| 2|            |
                                           | 2| 2| 2| 2| 8| 8| 2| 5| 0| 2| 2| 9| 6| 2| 2| 2| 2| 2| 2| 2| 9| 8| 3| 9| 7|            |
 _____________________________________________________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|     A      |
    200 PPM                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 __________________________________________________________________________________________________________________________________ 
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Lipoma                               |                               X                                          |          1 |
                                            __________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                                                          |          1 |
      Lipoma                               |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                                                          |          2 |
                                            __________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Hepatocellular Carcinoma             |                            X                                             |          1 |
      Leukemia Mononuclear                 |       X     X  X     X  X  X  X  X     X     X     X  X  X        X  X  X|         26 |
                                            __________________________________________________________________________|____________|
   Mesentery                               |             +           +                                         +      |   7        |
                                            __________________________________________________________________________|____________|
   Oral Mucosa                             |             +                             +                              |   2        |
      Pharyngeal, Squamous Cell Papilloma  |                                           X                              |          1 |
                                            __________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                                                         X|          4 |
      Acinus, Adenoma                      |                               X                                          |          1 |
                                            __________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                                                         X|          1 |
      Squamous Cell Papilloma              |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Tooth                                   |                                                                          |   1        |
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                                                          |          3 |
                                            __________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                  X                                       |          5 |
      Pheochromocytoma Benign              |    X        X  X     X           X     X     X        X     X     X      |         14 |
                                            __________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Adenoma                              |                                                                          |          1 |
 __________________________________________________________________________________________________________________________________ 

                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  

                                                             Page  49                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 6| 6| 6| 7| 5| 6| 7| 7| 7| 4| 7| 7| 7| 6| 7| 7| 7| 6| 5| 6| 5| 6|            |
                             DAY ON TEST   | 2| 2| 2| 6| 4| 4| 2| 8| 4| 2| 2| 1| 8| 2| 2| 2| 3| 2| 2| 2| 0| 3| 7| 2| 2|            |
                                           | 2| 2| 2| 2| 8| 8| 2| 5| 0| 2| 2| 9| 6| 2| 2| 2| 2| 2| 2| 2| 9| 8| 3| 9| 7|            |
 _____________________________________________________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|     A      |
    200 PPM                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 __________________________________________________________________________________________________________________________________ 
 ENDOCRINE SYSTEM - cont                   |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                X                 X                                       |          3 |
      Pars Distalis, Adenoma               |       X                 X                                   X  X         |         12 |
                                            __________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      C-Cell, Adenoma                      |    X                                                     X               |          3 |
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +|  49        |
      Mesothelioma Benign                  |                   X                                                      |          1 |
                                            __________________________________________________________________________|____________|
   Preputial Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +|  49        |
      Adenoma                              |                                                                      X   |          7 |
      Leukemia Mononuclear                 |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                  X                                      X|          4 |
                                            __________________________________________________________________________|____________|
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                                                         X|          2 |
                                            __________________________________________________________________________|____________|
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +|  49        |
      Bilateral, Interstitial Cell, Adenoma| X  X  X  X  X  X  X  X     X  X        X  X  X     X  X  X        X  X  X|         37 |
      Interstitial Cell, Adenoma           |                         X                                   X  X         |          6 |
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |             X                    X                                X      |          9 |
      Melanoma Malignant, Metastatic, Skin |                               X                                          |          1 |
                                            __________________________________________________________________________|____________|
   Lymph Node                              | +              +     +           +           +           +  +     +  +  +|  20        |
      Axillary, Leukemia Mononuclear       |                                                                          |          1 |
      Deep Cervical, Leukemia Mononuclear  |                X                                                         |          2 |
      Iliac, Leukemia Mononuclear          |                X                 X                                       |          8 |
      Mediastinal, Leukemia Mononuclear    |                X                 X                                X     X|         10 |
      Pancreatic, Leukemia Mononuclear     |                X     X           X                                X     X|         11 |
      Renal, Leukemia Mononuclear          |                X                 X           X           X        X  X   |         13 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                      X           X           X        X  X        X     X|         16 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |             X  X     X           X           X           X        X     X|         15 |
 __________________________________________________________________________________________________________________________________ 

                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  

                                                             Page  50                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 6| 6| 6| 7| 5| 6| 7| 7| 7| 4| 7| 7| 7| 6| 7| 7| 7| 6| 5| 6| 5| 6|            |
                             DAY ON TEST   | 2| 2| 2| 6| 4| 4| 2| 8| 4| 2| 2| 1| 8| 2| 2| 2| 3| 2| 2| 2| 0| 3| 7| 2| 2|            |
                                           | 2| 2| 2| 2| 8| 8| 2| 5| 0| 2| 2| 9| 6| 2| 2| 2| 2| 2| 2| 2| 9| 8| 3| 9| 7|            |
 _____________________________________________________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|     A      |
    200 PPM                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 __________________________________________________________________________________________________________________________________ 
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |       X     X  X     X  X  X  X  X     X     X     X  X  X        X  X  X|         25 |
                                            __________________________________________________________________________|____________|
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +|  48        |
      Leukemia Mononuclear                 |                                  X                       X        X     X|         10 |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Fibroadenoma                         | X                       X     X  X                    X        X         |          6 |
      Leukemia Mononuclear                 |                                  X                                       |          3 |
                                            __________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Keratoacanthoma                      |                                                                          |          1 |
      Keratoacanthoma, Multiple            |                                                                          |          1 |
      Squamous Cell Papilloma              |                                              X                           |          1 |
      Pinna, Melanoma Malignant            |                               X                                          |          1 |
      Subcutaneous Tissue, Fibroma         |    X                                                                     |          4 |
      Subcutaneous Tissue, Lipoma          |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +|  48        |
      Leukemia Mononuclear                 |                                  X                                X      |          6 |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Alveolar/Bronchiolar Carcinoma       |                                                                          |          2 |
      Leukemia Mononuclear                 |                                  X                                X     X|          9 |
      Melanoma Malignant, Metastatic, Skin |                               X                                          |          1 |
                                            __________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Leukemia Mononuclear                 |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Zymbal's Gland                          |                                     +                                    |   1        |
      Carcinoma                            |                                     X                                    |          1 |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 __________________________________________________________________________________________________________________________________ 

                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  

                                                             Page  51                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 7| 7| 6| 6| 6| 7| 5| 6| 7| 7| 7| 4| 7| 7| 7| 6| 7| 7| 7| 6| 5| 6| 5| 6|            |
                             DAY ON TEST   | 2| 2| 2| 6| 4| 4| 2| 8| 4| 2| 2| 1| 8| 2| 2| 2| 3| 2| 2| 2| 0| 3| 7| 2| 2|            |
                                           | 2| 2| 2| 2| 8| 8| 2| 5| 0| 2| 2| 9| 6| 2| 2| 2| 2| 2| 2| 2| 9| 8| 3| 9| 7|            |
 _____________________________________________________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|     A      |
    200 PPM                                | 2| 2| 2| 2| 3| 3| 3| 3| 3| 3| 3| 3| 3| 3| 4| 4| 4| 4| 4| 4| 4| 4| 4| 4| 5|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 __________________________________________________________________________________________________________________________________ 
 URINARY SYSTEM - cont                     |                                                                          |            |
                                           |                                                                          |            |
      Leukemia Mononuclear                 |                                  X                                X     X|          6 |
      Renal Tubule, Adenoma                |                               X                                          |          1 |
      Renal Tubule, Adenoma, Multiple      |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                  X                                      X|          4 |
 __________________________________________________________________________________________________________________________________ 
 SYSTEMIC LESIONS                          |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |       X     X  X     X  X  X  X  X     X     X     X  X  X        X  X  X|         26 |
      Mesothelioma Benign                  |                   X                                                      |          1 |
 __________________________________________________________________________________________________________________________________ 

                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  

                                                             Page  52                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 6| 6| 6| 6| 1| 6| 7| 7| 7| 6| 6| 5| 4| 7| 5| 6| 7| 6| 6| 5| 6| 7| 6| 5| 6|             
                             DAY ON TEST   | 3| 1| 4| 2| 9| 5| 2| 0| 2| 8| 9| 6| 4| 2| 2| 7| 2| 8| 4| 4| 7| 2| 9| 1| 9|             
                                           | 4| 6| 7| 2| 4| 1| 2| 0| 2| 1| 7| 2| 4| 2| 3| 5| 2| 5| 4| 3| 2| 2| 1| 5| 7|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|             
    400 PPM                                | 5| 5| 5| 5| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 7|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 ALIMENTARY SYSTEM                         |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Colon                  | +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 | X              X                                                         |             
                                            __________________________________________________________________________|             
   Intestine Small, Duodenum               | +  +  +  +  +  M  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 | X                                                                        |             
                                            __________________________________________________________________________|             
   Intestine Small, Jejunum                | +  +  +  +  +  M  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Intestine Small, Ileum                  | +  +  +  +  +  M  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 | X                                                                        |             
                                            __________________________________________________________________________|             
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Cholangiocarcinoma                   |                                                                          |             
      Hepatocellular Adenoma               |          X           X                                                   |             
      Hepatocellular Adenoma, Multiple     |                                                                          |             
      Leukemia Mononuclear                 | X  X           X     X     X     X  X           X        X  X     X  X  X|             
                                            __________________________________________________________________________|             
   Mesentery                               | +              +        +              +  +                              |             
      Leukemia Mononuclear                 |                X                                                         |             
                                            __________________________________________________________________________|             
   Pancreas                                | +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                                                      X  X|             
      Acinus, Adenoma                      |                                                                          |             
                                            __________________________________________________________________________|             
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Stomach, Forestomach                    | +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Stomach, Glandular                      | +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Tongue                                  |                                                    +                     |             
      Squamous Cell Papilloma              |                                                    X                     |             
 _____________________________________________________________________________________________________________________|             
 CARDIOVASCULAR SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                                 X                 X  X  X|             
 _____________________________________________________________________________________________________________________|             
 ENDOCRINE SYSTEM                          |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                                             X            |             
                                            __________________________________________________________________________|             
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                                             X            |             
      Pheochromocytoma Complex             |                                                                          |             
      Pheochromocytoma Benign              |                                        X     X                           |             
                                            __________________________________________________________________________|             
   Islets, Pancreatic                      | +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Parathyroid Gland                       | +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                                                   X      |             
      Pars Distalis, Adenoma               |    X  X                 X        X     X        X     X                  |             
                                            __________________________________________________________________________|             
   Thyroid Gland                           | +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      C-Cell, Adenoma                      |                   X                                                      |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  53                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 6| 6| 6| 6| 1| 6| 7| 7| 7| 6| 6| 5| 4| 7| 5| 6| 7| 6| 6| 5| 6| 7| 6| 5| 6|             
                             DAY ON TEST   | 3| 1| 4| 2| 9| 5| 2| 0| 2| 8| 9| 6| 4| 2| 2| 7| 2| 8| 4| 4| 7| 2| 9| 1| 9|             
                                           | 4| 6| 7| 2| 4| 1| 2| 0| 2| 1| 7| 2| 4| 2| 3| 5| 2| 5| 4| 3| 2| 2| 1| 5| 7|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|             
    400 PPM                                | 5| 5| 5| 5| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 7|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 GENERAL BODY SYSTEM                       |                                                                          |             
                                           |                                                                          |             
    None                                   |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 GENITAL SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Epididymis                              | +  M  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
                                            __________________________________________________________________________|             
   Preputial Gland                         | +  M  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Adenoma                              |                         X                                                |             
      Carcinoma                            |                                                                          |             
      Leukemia Mononuclear                 |                                                                   X      |             
                                            __________________________________________________________________________|             
   Prostate                                | +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                                                      X   |             
      Lymphoma Malignant                   |                                                    X                     |             
                                            __________________________________________________________________________|             
   Seminal Vesicle                         | +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +|             
      Leukemia Mononuclear                 |                                                                   X      |             
                                            __________________________________________________________________________|             
   Testes                                  | +  M  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Bilateral, Interstitial Cell, Adenoma| X        X     X  X     X  X  X     X  X  X  X  X  X     X  X  X  X  X  X|             
      Interstitial Cell, Adenoma           |                                                       X                  |             
 _____________________________________________________________________________________________________________________|             
 HEMATOPOIETIC SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 | X  X           X                                         X  X     X  X  X|             
                                            __________________________________________________________________________|             
   Lymph Node                              |    +     +     +           +  +        +           +     +  +     +  +   |             
      Axillary, Leukemia Mononuclear       |                                                                   X      |             
      Iliac, Leukemia Mononuclear          |    X                                                              X  X   |             
      Inguinal, Leukemia Mononuclear       |                                                                   X      |             
      Lumbar, Leukemia Mononuclear         |                                                                   X      |             
      Mediastinal, Leukemia Mononuclear    |    X           X                                         X  X     X      |             
      Pancreatic, Leukemia Mononuclear     |    X                                                              X  X   |             
      Renal, Leukemia Mononuclear          |    X                                                              X  X   |             
                                            __________________________________________________________________________|             
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 | X  X           X                                            X     X  X   |             
                                            __________________________________________________________________________|             
   Lymph Node, Mesenteric                  | +  +  +  +  M  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |    X           X                                         X  X     X      |             
                                            __________________________________________________________________________|             
   Spleen                                  | +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 | X  X           X           X     X  X           X     X  X  X     X  X  X|             
                                            __________________________________________________________________________|             
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 | X  X           X                                            X     X  X   |             
      Thymoma Benign                       |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM                      |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +|             
      Fibroadenoma                         |                      X     X                                      X      |             
      Leukemia Mononuclear                 |                                                                   X      |             
                                            __________________________________________________________________________|             
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Basal Cell Adenoma                   |                      X                                                   |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  54                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 _____________________________________________________________________________________________________________________              
                                           | 6| 6| 6| 6| 1| 6| 7| 7| 7| 6| 6| 5| 4| 7| 5| 6| 7| 6| 6| 5| 6| 7| 6| 5| 6|             
                             DAY ON TEST   | 3| 1| 4| 2| 9| 5| 2| 0| 2| 8| 9| 6| 4| 2| 2| 7| 2| 8| 4| 4| 7| 2| 9| 1| 9|             
                                           | 4| 6| 7| 2| 4| 1| 2| 0| 2| 1| 7| 2| 4| 2| 3| 5| 2| 5| 4| 3| 2| 2| 1| 5| 7|             
 _____________________________________________________________________________________________________________________|             
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|             
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1|             
    400 PPM                                | 5| 5| 5| 5| 5| 5| 5| 5| 5| 6| 6| 6| 6| 6| 6| 6| 6| 6| 6| 7| 7| 7| 7| 7| 7|             
                                           | 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5|             
 _____________________________________________________________________________________________________________________|             
 INTEGUMENTARY SYSTEM - cont               |                                                                          |             
                                           |                                                                          |             
      Keratoacanthoma                      |                            X                                             |             
      Trichoepithelioma                    |                                                                          |             
      Pinna, Melanoma Malignant            |                                                                          |             
 _____________________________________________________________________________________________________________________|             
 MUSCULOSKELETAL SYSTEM                    |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 NERVOUS SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 | X              X                                         X        X      |             
 _____________________________________________________________________________________________________________________|             
 RESPIRATORY SYSTEM                        |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Alveolar/Bronchiolar Adenoma         |                                                                         X|             
      Leukemia Mononuclear                 | X  X           X     X                          X        X  X     X  X   |             
                                            __________________________________________________________________________|             
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                X                                                         |             
                                            __________________________________________________________________________|             
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
 _____________________________________________________________________________________________________________________|             
 SPECIAL SENSES SYSTEM                     |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Ear                                     |                                                                          |             
                                            __________________________________________________________________________|             
   Zymbal's Gland                          |                                  +                                       |             
      Carcinoma                            |                                  X                                       |             
 _____________________________________________________________________________________________________________________|             
 URINARY SYSTEM                            |                                                                          |             
                                           |                                                                          |             
                                            __________________________________________________________________________|             
   Kidney                                  | +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                X                                                  X  X  X|             
      Renal Tubule, Adenoma                |                                                             X            |             
      Renal Tubule, Adenoma, Multiple      |                                                       X                  |             
                                            __________________________________________________________________________|             
   Urinary Bladder                         | +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 |                                                             X     X      |             
 _____________________________________________________________________________________________________________________|             
 SYSTEMIC LESIONS                          |                                                                          |             
                                            __________________________________________________________________________|             
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|             
      Leukemia Mononuclear                 | X  X           X     X     X     X  X           X     X  X  X     X  X  X|             
      Lymphoma Malignant                   |                                                    X                     |             
 _____________________________________________________________________________________________________________________|             

                                                             Page  55                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 4| 7| 7| 6| 7| 7| 6| 7| 7| 7| 6| 6| 7| 6| 6| 5| 7| 7| 5| 7| 7| 5| 4| 7|            |
                             DAY ON TEST   | 1| 2| 2| 2| 7| 1| 2| 4| 2| 2| 2| 2| 7| 2| 9| 0| 8| 2| 1| 9| 2| 2| 2| 6| 2|            |
                                           | 9| 8| 2| 2| 0| 9| 2| 7| 2| 2| 2| 7| 6| 2| 1| 1| 4| 2| 7| 8| 2| 2| 0| 5| 2|            |
 _____________________________________________________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2|     A      |
    400 PPM                                | 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 8| 8| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 0|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 __________________________________________________________________________________________________________________________________ 
 ALIMENTARY SYSTEM                         |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Esophagus                               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Colon                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Rectum                 | +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                            __________________________________________________________________________|____________|
   Intestine Large, Cecum                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Leukemia Mononuclear                 |                                                                          |          2 |
                                            __________________________________________________________________________|____________|
   Intestine Small, Duodenum               | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
      Leukemia Mononuclear                 |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Intestine Small, Jejunum                | +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  47        |
                                            __________________________________________________________________________|____________|
   Intestine Small, Ileum                  | +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  47        |
      Leukemia Mononuclear                 |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Liver                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Cholangiocarcinoma                   |                                                    X                     |          1 |
      Hepatocellular Adenoma               |                                                                          |          2 |
      Hepatocellular Adenoma, Multiple     |                         X                                                |          1 |
      Leukemia Mononuclear                 | X        X              X  X  X     X  X  X  X  X  X              X  X   |         26 |
                                            __________________________________________________________________________|____________|
   Mesentery                               |                                  +        +  +                           |   8        |
      Leukemia Mononuclear                 |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Pancreas                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Leukemia Mononuclear                 |                                                                          |          2 |
      Acinus, Adenoma                      |                                                             X            |          1 |
                                            __________________________________________________________________________|____________|
   Salivary Glands                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
                                            __________________________________________________________________________|____________|
   Stomach, Forestomach                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                            __________________________________________________________________________|____________|
   Stomach, Glandular                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                            __________________________________________________________________________|____________|
   Tongue                                  |                                                                          |   1        |
      Squamous Cell Papilloma              |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 CARDIOVASCULAR SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Heart                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                                                          |          4 |
 _____________________________________________________________________________________________________________________|            |
 ENDOCRINE SYSTEM                          |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Adrenal Cortex                          | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Adrenal Medulla                         | +  +  +  +  +  +  +  +  +  +  +  +  M  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Leukemia Mononuclear                 |                                                                      X   |          2 |
      Pheochromocytoma Complex             |                                                             X            |          1 |
      Pheochromocytoma Benign              |                            X  X                                          |          4 |
                                            __________________________________________________________________________|____________|
   Islets, Pancreatic                      | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
                                            __________________________________________________________________________|____________|
   Parathyroid Gland                       | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
 __________________________________________________________________________________________________________________________________ 

                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  

                                                             Page  56                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 4| 7| 7| 6| 7| 7| 6| 7| 7| 7| 6| 6| 7| 6| 6| 5| 7| 7| 5| 7| 7| 5| 4| 7|            |
                             DAY ON TEST   | 1| 2| 2| 2| 7| 1| 2| 4| 2| 2| 2| 2| 7| 2| 9| 0| 8| 2| 1| 9| 2| 2| 2| 6| 2|            |
                                           | 9| 8| 2| 2| 0| 9| 2| 7| 2| 2| 2| 7| 6| 2| 1| 1| 4| 2| 7| 8| 2| 2| 0| 5| 2|            |
 _____________________________________________________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2|     A      |
    400 PPM                                | 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 8| 8| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 0|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 __________________________________________________________________________________________________________________________________ 
 ENDOCRINE SYSTEM - cont                   |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Pituitary Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                         X                    X                           |          3 |
      Pars Distalis, Adenoma               |    X                             X                    X  X               |         11 |
                                            __________________________________________________________________________|____________|
   Thyroid Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      C-Cell, Adenoma                      |                            X                                             |          2 |
 _____________________________________________________________________________________________________________________|            |
 GENERAL BODY SYSTEM                       |                                                                          |            |
                                           |                                                                          |            |
    None                                   |                                                                          |            |
 _____________________________________________________________________________________________________________________|            |
 GENITAL SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Epididymis                              | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
                                            __________________________________________________________________________|____________|
   Preputial Gland                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
      Adenoma                              |       X                                                                  |          2 |
      Carcinoma                            |                               X                                          |          1 |
      Leukemia Mononuclear                 |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Prostate                                | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Leukemia Mononuclear                 |                                           X                              |          2 |
      Lymphoma Malignant                   |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Seminal Vesicle                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
      Leukemia Mononuclear                 |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Testes                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
      Bilateral, Interstitial Cell, Adenoma| X     X  X  X  X  X  X  X  X  X     X  X  X  X  X  X  X     X  X     X  X|         40 |
      Interstitial Cell, Adenoma           |                                  X                                X      |          3 |
 _____________________________________________________________________________________________________________________|            |
 HEMATOPOIETIC SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone Marrow                             | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                              X                    X  X   |         11 |
                                            __________________________________________________________________________|____________|
   Lymph Node                              |          +              +     +     +     +  +     +  +  +     +  +  +   |  23        |
      Axillary, Leukemia Mononuclear       |                                                                          |          1 |
      Iliac, Leukemia Mononuclear          |                                     X     X                              |          5 |
      Inguinal, Leukemia Mononuclear       |                               X                                          |          2 |
      Lumbar, Leukemia Mononuclear         |                                                                          |          1 |
      Mediastinal, Leukemia Mononuclear    |                                           X  X                    X  X   |          9 |
      Pancreatic, Leukemia Mononuclear     |                                     X                             X      |          5 |
      Renal, Leukemia Mononuclear          |                         X     X     X     X                              |          7 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mandibular                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                         X           X           X                 X  X   |         11 |
                                            __________________________________________________________________________|____________|
   Lymph Node, Mesenteric                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  48        |
      Leukemia Mononuclear                 | X                       X                 X                          X   |          9 |
 __________________________________________________________________________________________________________________________________ 

                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  

                                                             Page  57                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 4| 7| 7| 6| 7| 7| 6| 7| 7| 7| 6| 6| 7| 6| 6| 5| 7| 7| 5| 7| 7| 5| 4| 7|            |
                             DAY ON TEST   | 1| 2| 2| 2| 7| 1| 2| 4| 2| 2| 2| 2| 7| 2| 9| 0| 8| 2| 1| 9| 2| 2| 2| 6| 2|            |
                                           | 9| 8| 2| 2| 0| 9| 2| 7| 2| 2| 2| 7| 6| 2| 1| 1| 4| 2| 7| 8| 2| 2| 0| 5| 2|            |
 _____________________________________________________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2|     A      |
    400 PPM                                | 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 8| 8| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 0|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 __________________________________________________________________________________________________________________________________ 
 HEMATOPOIETIC SYSTEM - cont               |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Spleen                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Leukemia Mononuclear                 | X        X              X  X  X     X  X  X  X  X  X              X  X   |         26 |
                                            __________________________________________________________________________|____________|
   Thymus                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                         X           X        X  X                    X   |         11 |
      Thymoma Benign                       |                                        X                                 |          1 |
 _____________________________________________________________________________________________________________________|            |
 INTEGUMENTARY SYSTEM                      |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Mammary Gland                           | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Fibroadenoma                         |                         X                                                |          4 |
      Leukemia Mononuclear                 |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Skin                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Basal Cell Adenoma                   |                                                                          |          1 |
      Keratoacanthoma                      | X           X                          X              X                  |          5 |
      Trichoepithelioma                    |       X                                                                  |          1 |
      Pinna, Melanoma Malignant            |                                                 X                    X   |          2 |
 _____________________________________________________________________________________________________________________|            |
 MUSCULOSKELETAL SYSTEM                    |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Bone                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 NERVOUS SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Brain                                   | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                              X                           |          5 |
 _____________________________________________________________________________________________________________________|            |
 RESPIRATORY SYSTEM                        |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Lung                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Alveolar/Bronchiolar Adenoma         |                         X                                      X        X|          4 |
      Leukemia Mononuclear                 |                                     X        X                       X   |         12 |
                                            __________________________________________________________________________|____________|
   Nose                                    | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 |                                                                          |          1 |
                                            __________________________________________________________________________|____________|
   Trachea                                 | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
 _____________________________________________________________________________________________________________________|            |
 SPECIAL SENSES SYSTEM                     |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Ear                                     |                                                 +                    +   |   2        |
                                            __________________________________________________________________________|____________|
   Zymbal's Gland                          |                                                                          |   1        |
      Carcinoma                            |                                                                          |          1 |
 _____________________________________________________________________________________________________________________|            |
 URINARY SYSTEM                            |                                                                          |            |
                                           |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Kidney                                  | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Leukemia Mononuclear                 |                                              X                           |          5 |
 __________________________________________________________________________________________________________________________________ 

                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  

                                                             Page  58                                                               
NTP Experiment-Test: 55301-05                        NEOPLASMS BY INDIVIDUAL ANIMAL                               Report: PEIRPT04
Study Type: CHRONIC                                              PYRIDINE                                         Date: 10/08/97  
Route: DOSED WATER                                                                                                Time: 11:10:29  
                                                                                                                                    
 __________________________________________________________________________________________________________________________________ 
                                           | 7| 4| 7| 7| 6| 7| 7| 6| 7| 7| 7| 6| 6| 7| 6| 6| 5| 7| 7| 5| 7| 7| 5| 4| 7|            |
                             DAY ON TEST   | 1| 2| 2| 2| 7| 1| 2| 4| 2| 2| 2| 2| 7| 2| 9| 0| 8| 2| 1| 9| 2| 2| 2| 6| 2|            |
                                           | 9| 8| 2| 2| 0| 9| 2| 7| 2| 2| 2| 7| 6| 2| 1| 1| 4| 2| 7| 8| 2| 2| 0| 5| 2|            |
 _____________________________________________________________________________________________________________________|     T (*)  |
                                           | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     O      |
   FISCHER 344 RATS MALE                   | 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0| 0|     T      |
                               ANIMAL ID   | 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1| 2|     A      |
    400 PPM                                | 7| 7| 7| 7| 8| 8| 8| 8| 8| 8| 8| 8| 8| 8| 9| 9| 9| 9| 9| 9| 9| 9| 9| 9| 0|     L      |
                                           | 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0|            |
 __________________________________________________________________________________________________________________________________ 
 URINARY SYSTEM - cont                     |                                                                          |            |
                                           |                                                                          |            |
      Renal Tubule, Adenoma                | X                                                     X                 X|          4 |
      Renal Tubule, Adenoma, Multiple      |                                                             X            |          2 |
                                            __________________________________________________________________________|____________|
   Urinary Bladder                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  49        |
      Leukemia Mononuclear                 |                                                                          |          2 |
 __________________________________________________________________________________________________________________________________ 
 SYSTEMIC LESIONS                          |                                                                          |            |
                                            __________________________________________________________________________|____________|
   Multiple Organs                         | +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +  +|  50        |
      Leukemia Mononuclear                 | X        X              X  X  X     X  X  X  X  X  X              X  X   |         27 |
      Lymphoma Malignant                   |                                                                          |          1 |
 __________________________________________________________________________________________________________________________________ 

                         * : Total animals with tissue examined microscopically; total animals with tumor                           
                         + : Tissue examined microscopically                      M : Missing tissue                                
                         X : Lesion present                                       A : Autolysis precludes evaluation                
                         I : Insufficient tissue                              BLANK : Not examined microscopically                  

                                                             Page  59                                                               
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