The most desirable method of treatment is the administration of large doses of iodide of potassium in a drench, or in the drinking water. The dose is from one to three drachms daily for a period of seven to fourteen days. The size of the dose depends on the size of the animal and its susceptibility to iodism. An animal weighing 1000 pounds may be given two drachms. The treatment is kept up until the symptoms of iodism develop. The condition is indicated by a loss of appetite and a catarrhal discharge from the eyes and nostrils. When this occurs, the treatment should be stopped, and the animal drenched with one-half pound of Epsom salts, and the dose repeated after three or four days. After an interval of two weeks, the iodide of potassium treatment should be repeated if the growth of the tumor is not checked. EMPHYSEMATOUS ANTHRAX, "BLACK LEG."--"Black leg" is an acute infectious disease of cattle that is characterized by lameness and superficial swellings in the region of the shoulder, quarter or neck. The swellings are hot and painful and usually contain gas. _The specific cause_ of "black leg" is a rod-shaped, spore-producing germ, the bacillus of emphysematous anthrax (Fig. 119). This germ possesses great vitality, and may live indefinitely in the soil. It has been known to live for years in clay and undrained soils. Young animals that are in high condition are predisposed to the disease. The germ enters the body through abrasions in the skin and mucous membrane of the mouth and intestines. "Black leg" is a common disease of young cattle in all sections of the country where cattle-raising is engaged in extensively. Outbreaks of the disease are most prevalent in the early spring after the snow has melted, and in the late summer in localities where cattle graze over the dried-up ponds and swampy places in the pasture. The germs of black leg may be carried from a farm where the disease is prevalent to non-infected premises by surface water. The opening up of drainage ditches through stock-raising communities may be followed by outbreaks of the disease. [Illustration: FIG. 119.--Bacillus of emphysematous anthrax.] _The symptoms_ of black leg develop quickly and may terminate fatally in a few hours. These are general dulness, stiffness, prostration and loss of appetite. Lameness is a prominent symptom. The animal may show a swelling in the regions of the shoulder and hindquarters or on other parts of the body. The swelling is very hot and painful at first, but if the animal lives for a time, it becomes less tender, crackles when pressed on and the skin may feel cold and leathery. Fever is a constant symptom. In the highly acute form of the disease nervous symptoms, such as convulsions and coma, occur. _The tissue changes_ in the region of the swelling are characteristic. An incision into the swelling shows a bloody, dark exudate and the surface of the muscular tissue is dark. Frothy, bloody liquid escapes from the mouth, nose and anus.