TUBERCULOSIS ( in animals). Viewing the evidence at hand, investigators have attribut ed the various forms of tuberculosis in animals to Bacillus tuberculosis. Birds are commonly supposed to be affected by a different form, but the differences observed are also considered to be due to differences in the anatomy and resisting power of different animals. Ilorses, sheep, goats, dogs, and cats are rarely affected; poultry and parrots frequently; cattle and hogs most com monly. European and American statistics from tuberculin tests and from meat inspection indi cate that from 10 to 50 per cent. of the cattle examined are affected. Tubercles may he found locally or generally distributed in the respiratory, alimentary, and lymphatic structures and in the bones of the animal examined. The popular no tion that tuberculosis in man is caused by the consumption of tuberculous meat and milk is without sure proof, and obviously experiments cannot be made to determine this point. Since, however, such food products are feared, and since they suggest uncleanness and negligence on the part of both producer and consumer, they should be avoided. Governmental inspection of dairies and meat has wrought great improvements in the sanitary conditions of stock and dairy farms, and methods of handling milk and meat, and has educated the public to demand pure animal prod ucts. The danger is far less than is generally
supposed, since experiments indicate that milk from cows suspected to be tuberculous may lie fed to calves without danger, and when pasteur ized it may be used as human food with no unto ward results.
For the detection of incipient cases of tubercu losis in cattle tuberculin is usually employed. This substance contains what is called the toxin produced during the growth of the bacillus, but does not contain the living organism. When in jected into healthy cattle tuberculin produces no reaction, hut in affected cattle an elevation of from to 3° or more of the body temperature and a slight swelling at the point of injection are looked for. Animals which show- these symptoms are considered tuberculous and are separated from the rest of the herd. If they are valuable they may he used for breeding purposes, since the progeny rarely exhibit tuberculous symptoms. The calves are usually separated from their mothers very soon after birth. No reliable medical treatment has been discovered, though repeated injections of tuberculin have in some instances appeared to he slightly curative. Some cases recover spontaneously. Preventive meas ures are cleanliness, airy quarters, pure water and food, and free range upon good, well-man aged pastures.