There are two points to be noted in an animal about to be killed, namely, whether the animal is healthy, that is, free from disease,--and whether it is in proper condition, neither too young nor too old, is well-grown and well-nourished. Among the diseases to which animals are subject, some are objectionable because of the possibility of the direct transmission of their disease to those eating the flesh, while others are objectionable because the flesh is spoiled and so causes irritation in the stomach and intestines of those eating it. Among the former diseases may be mentioned trichinosis, tuberculosis, and measles of pigs. In the latter category are animals suffering from such diseases as epidemic pneumonia, foot-and-mouth disease, Texas fever, anthrax, hog cholera, and others in which a general toxic condition of the animal's system results from the disease. Toxins are thus formed in the body which may pass to the human being eating the flesh, and in this way poisons called ptomaines are produced, resulting in so-called toxic poisoning. It is not the function of this book to describe the symptoms peculiar to each of these diseases, and it is here sufficient to say that the flesh of no animal apparently suffering from any disease should be used for food. The unhealthy animal can usually be recognized by a casual examination, without undertaking to define the specific disease from which the animal is suffering, characterized by such an examination. When sick, according to Parkes, the coat of the animal is rough or standing, the nostrils are dry or covered with foam, the eyes are heavy, the tongue protrudes, the respiration is difficult, the movements are slow and uncertain, and the various organs of the body perform their functions abnormally. On the other hand, the healthy animal moves freely, has a bright eye and moist nostril and a clear skin, the respiration is not hurried and the breath has no unpleasant odor, the circulation is tranquil, and the appetite good, thirst not excessive, and, if ruminant, when in repose, chews the cud. There is, however, one exception to this general rule, and that is in the case of tuberculosis, since the most scientific observations have failed to trace any connection between the inception of tuberculosis in man and the eating of meat from tuberculous animals, or to show any evil effects to man from eating the flesh of cows affected in the first stages of tuberculosis. The regulations of the United States Department of Agriculture on this point are as follows:---- "All carcasses affected with tuberculosis and showing emaciation shall be condemned. All other carcasses affected with tuberculosis shall be condemned, except those in which the lesions are slight, calcified, or encapsulated, and are confined to certain tissues ... and excepting also those which may ... be rendered into lard or tallow."