This volume is one of a set of illustrated studies of natural and experimental lesions in laboratory animals (rat, mouse and hamster). Precise differential diagnostic criteria and terminology are given. Useful data on pathogenesis, aetiology, biologic behaviour, frequency in different strains and under varying laboratory conditions are included. The significa nce of each lesion is considered, and comparisons are made with other species, including man. These monographs on the pathology of laboratory animals are designed to improve communication among those involved in the safety testing of foods, drugs and chemicals. Each volume covers a particular organ system and is intended for use by pathologists, toxicologists and others concerned with evaluating toxicity and carcinogenicity studies. This volume deals specifically with the cardiovascular system and the musculoskeletal systems. This monograph on toxicology and pathology is intended for researchers and government regulatory scientists.