DISPOSING OF DEAD HOGS.--The carcasses of the dead hogs should be burned. Before placing the carcass on the fire, it should be cut open and several long incisions made through the skin. A crematory may be made by digging two cross trenches that are about one foot deep at the point where they cross, and shallow at the ends. Iron bars or pipe may be laid over the trenches where they cross for the carcass to rest upon, or woven wire fencing securely fastened with stakes may be used in the place of the iron bars. If the carcass is disposed of by burying, it should be buried at least four feet deep and covered with quicklime. DISINFECTING THE YARDS AND HOUSES.--If the sick hogs are moved to new quarters at the beginning of the outbreak, the hog houses and yards should be cleaned and disinfected (Fig. 84). The manure and all other litter should be hauled away to a field where there is no danger from this infectious material becoming scattered about the premises, leaving a centre of infection in the neighborhood and causing outbreaks of cholera among neighboring herds. It may be advisable to burn the corn-cobs and other litter that have accumulated about the yards. Loose board floors should be torn up and the manure from beneath removed. Portable houses should be removed. The floors, walls of the house and fences should be first cleaned by scraping off the filth, and then sprayed with a three per cent water solution of a cresol or coal tar disinfectant to which sufficient lime has been added to make a thin whitewash. Three or four months of warm, sunny weather are sufficient to destroy the cholera infection in well-cleaned yards. ANTI-HOG-CHOLERA SERUM.--The credit of developing the first and at present the only reliable anti-hog-cholera serum and method of vaccination belongs to Drs. Dorset and Niles. Anti-hog-cholera serum came into general use in 1908, and all of the swine-producing States have established State laboratories for the production of this serum. Anti-hog-cholera serum is produced by injecting directly, or indirectly, into the blood-vessels of an immune hog a large quantity of cholera virus, secured by bleeding a hog that is fatally sick with acute cholera, and bleeding the injected animal after it has completely recovered from the injection. The injection of the cholera blood is for the purpose of stimulating the production of antibodies by the body tissues, and raising the protective properties of the immune hog's blood. An animal so treated is called a hyperimmune (Fig. 85). The blood from the hyperimmunes is defibrinated and a preservative added, and after it has been tested for potency and freedom from contaminating organisms, it is ready for use. [Illustration: FIG. 85.--Hyperimmune hogs used for the production of anti-hog-cholera serum.]