Tetanus or lockjaw is not infectious, but is conveyed to man by the inoculation of a wound by dirt or earth which contains the tetanus bacillus. For this reason it is more apt to follow injuries to the hands or feet. Extreme cleanliness of wounds is the only practicable preventive means. Little is known of the history of the tetanus bacillus outside the body; and as to what soils contain it most abundantly. Wounds contaminated by horse manure appear to be especially dangerous.
GLANDERS.
Glanders is common in horses. It attacks the mucous membrane of the nose, causing ulceration. It is extremely infectious. Farcy is a more chronic form of the same disease, in which the so-called “farcy-buds” are produced. Its prevention can best be ensured by killing both actually diseased and suspected animals, if the latter give a reaction to mallein. Mallein is a product allied to tuberculin, obtained from cultivations of the bacillus of glanders. It sets up febrile reaction in glandered, but not in healthy horses. Further preventive measures are the temporary closing of public drinking fountains for horses, and the thorough cleansing and disinfection of stables. Men, especially grooms, are sometimes infected by the horse, and the disease is commonly fatal.
HYDROPHOBIA.
Hydrophobia is the disease in man which is caused by the bite of a dog or other animal suffering from rabies. It is seldom if ever communicated otherwise than by inoculation. The incubation period in the dog varies from three to six weeks, and in man is usually about the same; but occasionally it is much longer, occasionally even more than a year.
At the Pasteur Institute, Paris, patients who have been bitten by rabid dogs are treated by the inoculation of an attenuated virus of rabies derived from rabbits, with promising results.
Dogs only acquire rabies from dogs or other animals already rabid. So far as is known, it does not arise de novo. Hence the necessity for an extensive area of muzzling when cases of rabies occur. The enforcement of this plan has greatly reduced the amount of hydrophobia in this country in recent years. There has been much misplaced sympathy with dogs on this score. In the dog the symptoms of rabies occur in three stages: a premonitory stage, in which the dog’s habits change, he becomes morose and quiet, and dribbles; a second stage, in which he has paroxysms of fury, his voice is high-toned and croupy, and he cannot swallow water; and a third or paralytic stage, in which his jaws drop, he drags his hind legs and soon dies.
ERYSIPELAS.
Erysipelas occurs on various parts of the skin. It is caused by the inoculation through an abraded surface of a virulent form of the same streptococcus that commonly causes suppuration. It occurs chiefly in debilitated subjects. Some persons are specially prone to it, and may have many attacks. Erysipelas, like scarlet fever, occurs most in years in which there is deficient rainfall; and is probably conveyed by dust. It may spread, though exceptionally, from case to case.