The Liver.- Neoplasms.- Foci of Altered Hepatocytes, Rat.- Foci of Altered Hepatocytes, Mouse.- Hepatocellular Adenoma, Liver, Rat.- Hepatocellular Carcinoma, Liver, Rat.- Cholangiofibroma and Cholangiocarcinoma, Liver, Rat.- Cholangioma, Liver, Rat.- Hemangiosarcoma, Liver, Rat.- Hemangioma, Liver, Rat.- Hepatoblastoma, Mouse.- Kupffer's Cell Sarcoma, Liver, Rat.- Spongiosis Hepatis and Spongiotic Pericytoma, Rat.- Focal Carcinoma in Hepatocellular Adenoma, Liver, Mouse.- Hyperplasia, Adenoma, Gallbladder, Hamster.- Mesothelioma, Peritoneum, Induced by Mineral Fibers, Rat.- Non-neoplastic Lesions.- Polyploidy, Liver, Rat.- Intranuclear and Intracytoplasmic Inclusions, Liver, Rat.- Extramedullar Hematopoiesis, Liver, Rat.- Nutritional Fatty Liver, Cirrhosis, and Hepatocellular Carcinoma, Rat, Mouse.- Cirrhosis, Mouse.- Peliosis Hepatis, Rodents.- Hyperplasia, Diffuse, Following Partial Hepatectomy, Mouse.- Oval Cells in Rodent Liver, Mouse, Rat.- Herniation of Liver Through Esophageal Hiatus, Rat.- Viral Infections.- K Virus Infection, Mouse.- Mouse Hepatitis Virus Infection, Liver, Mouse.- Rat Parvovirus Infection, Liver.- Mousepox, Liver, Mouse.- Reovirus Type 3 Infection, Liver, Mouse.- Bacterial Infections.- Tyzzer's Disease in the Rat, Mouse, and Hamster.- Corynebacterium kutscheri Infection, Liver, Mouse and Rat.- Idiopathic Focal Hepatic Necrosis in Inbred Mice.- Multifocal Inflammation, Liver, Rat.- The Salivary Glands.- Histology and Ultrastructure, Salivary Glands, Mouse.- Neoplasms.- Myoepithelioma, Salivary Glands, Mouse.- Adenoma, Adenocarcinoma, Salivary Gland, Mouse.- Polyoma Virus Infection, Salivary Glands, Mouse.- Non-neoplastic Lesions.- Cytomegalovirus Infection, Salivary Glands, Mouse, Rat, and Hamster.- Sialodacryoadenitis (SDA) VirusInfection, Rat.- The Exocrine Pancreas.- Embryology, Histology, and Ultrastructure of the Exocrine Pancreas.- Neoplasms.- Acinar Cell Carcinoma, Pancreas, Rat.- Experimental Carcinogenesis, Exocrine Pancreas, Hamster and Rat.- Non-neoplastic Lesions.- Atrophy, Exocrine Pancreas, Rat.- Exocrine Pancreas of Hypophysectomized Rats.- Necrotizing Pancreatitis Induced by 4-Hydroxyaminoquinoline, Rat.- The Oral Cavity.- Squamous Cell Carcinoma, Tongue, Rat.- The Esophagus.- Neoplasms.- Squamous Cell Papilloma, Esophagus, Rat.- Carcinoma In Situ, Esophagus, Rat.- Squamous Cell Carcinoma, Esophagus, Rat.- Papillary and Nonpapillary Squamous Cell Carcinoma, Esophagus, Rat (Zinc Deficiency, Alcohol, and Methylbenzylnitrosamine).- Adenocarcinoma, Esophagus, Rat.- Adenosquamous Carcinoma, Esophagus, Rat.- The Stomach.- Anatomy, Histology, Ultrastructure, Stomach, Rat.- Neoplasms.- Papilloma, Forestomach, Rat.- Squamous Cell Carcinoma Forestomach, Rat.- Adenoma, Glandular Stomach, Rat.- Adenocarcinoma, Glandular Stomach, Rat.- Leiomyoma and Leiomyosarcoma, Stomach, Rat.- The Small Intestines.- Viral Infections.- Mouse Hepatitis Virus Infection, Intestine, Mouse.- Murine Rotavirus Infection, Intestine, Mouse.- Adenovirus Infection, Intestine, Mouse, Rat.- Infectious Diarrhea of Infant Rats (Rotavirus).- Bacterial Infections.- Clostridial Enteropathies, Hamster.- Citrobacter freundii Infection, Colon, Mouse.- Proliferative Ileitis, Hamster.- Streptococcal Enteropathy, Intestine, Rat.- Helminth and Protozoal Infections.- Spironucleus muris Infection, Intestine, Mouse, Rat, and Hamster.- Giardia muris Infection, Intestine, Mouse, Rat, and Hamster.- The Large Intestine.- Bacterial Infection.- Coliform Typhlocolitis, Immunodeficient Mice.- Neoplasms.- Adenocarcinoma, Colon and Rectum, Rat.