In the field of public health the veterinarian plays an important role in the prevention of the spread of diseases from animals to man. Not only for his own protection but for protection of his clients and the livestock of his clients, the veterinarian should be familiar with the diseases of the cat and dog and the part these animals play in transmitting infections to man and other animals. Although there are diseases which are peculiar only to the cat and dog, these pets are also susceptible to certain diseases of other animals and man.