HOG CHOLERA 279 



they may be shipped in infected cars, they may pass 

 through infected localities, and they may come in contact 

 with diseased animals en route. This is especially true if 

 they pass through stock yards and thus get the disease 

 which will manifest itself after the pig reaches its destina- 

 tion, and if not quarantined may inoculate the entire herd. 



GOVERNMENT HOG CHOLERA SERUM. 



The Bureau of Animal Industry of the United States 

 Department of Agriculture has developed a serum which, 

 by means of vaccination, will render hogs immune (not 

 subject) to hog cholera. 



Preparation of the Serum. — In order to prepare this 

 serum an immune hog must first be obtained, either one 

 that is naturally immune to the disease or one that has 

 been rendered immune artificially. This hog is hyper- 

 immunized. This consists of inoculating him in the mus- 

 cles of the thigh with about 1000 c. c* of virulent hog 

 cholera blood, from which the clot has been removed, per 

 hundred pounds live weight of hog. The hypodermic in- 

 oculation consists simply in placing the inoculating fluid 

 beneath the skin or in the muscle of the hog, which is 

 done by means of a syringe that has a hollow pointed 

 needle. The syringe is filled, the needle forced through 

 the skin, and the contents expelled. But in the case of 

 inoculations of this kind this fluid is usually forced into 

 the muscles of the thigh, in which form it is more satis- 

 factory. There are two ways in which this hyper-im- 

 munization is brought about. First, the inoculating fluid, 

 or the 1000 c. c. of virulent hog cholera serum which is 

 injected into a hundred-pound pig, may be injected at one 

 and the same time. This is called the quick method. The 

 slow method consists in using a part of this amount of 



♦Cubic centimeters 



