280 SWINE 



serum at one time, taking a small quantity to begin with, 

 after a week a larger quantity, and still later a larger 

 quantity still, until the entire amount is used in three or 

 four inoculations. When an immune hog is thus inocu- 

 lated, it is said to have been hyper-immunized. 



If a naturally immune hog is not at hand, or cannot be 

 obtained, and the serum is to be prepared, a hog must 

 first be made immune as will be described later in the 

 regular process of protecting hogs from hog cholera, and 

 following this h€ is hyper-immunized as already stated ; 

 that is, by being inoculated with 1000 c. c. of defibrinated 

 hog cholera serum from a hog that is sick with hog 

 cholera. This may be done by the quick method, inject- 

 ing the serum all at once, or by the slow method by which 

 it is injected at three or four different times, starting 

 with a relatively small proportion of this quantity and 

 then gradually using larger quantities in successive weeks 

 thereafter. 



About a week after the injection of the serum in the 

 process of hyper-immunization, the hog is ready to have 

 his blood drawn for the regular process of protecting hogs 

 from hog cholera. The blood may be drawn by two proc- 

 esses: The hog may be killed and his entire quantity of 

 blood taken at once, or he may be bled at the tail. The 

 latter method is usually resorted to. The tail is thor- 

 oughly cleaned and disinfected with an antiseptic solu- 

 tion and then the end is cut off so as to allow the blood 

 to flow out, which is caught in a sterilized bottle under 

 antiseptic conditions, or under conditions such that it 

 does not become infected with foreign germs of any kind. 

 By this method, from 300 to 600 c. c. of blood may be 

 obtained at one time. This is repeated two or three times 

 at intervals of a week. It cannot be carried on longer 



