84 HOG CHOLEKA 



hams) is thoroughly scrubbed with antiseptic so- 

 lution. Then two mils of virus are injected into 

 one armpit, and the required quantity of serum 

 (about 35 mils for a 100 pound pig) is injected 

 into the other. Deep injections are desirable. 



Following this treatment the pig undergoes a 

 reaction beginning in about five days and lasting 

 about a week, during which time a permanent im- 

 munity to hog cholera is established. It is de- 

 sirable to immunize prospective hypers as com- 

 paratively young shoats and to delay hypering 

 until they have attained a weight of at least two 

 hundred pounds, as a long interval between the 

 date of immunizing and that of hypering favors 

 potent serum. In no instance should this interval 

 be less than sixty days. 



The Virus Pig 



In order that the immune may receive addi- 

 tional virus and become a hyper, a supply of virus 

 must be procured. This is done by injecting sus- 

 ceptible shoats with lethal doses of hog cholera 

 virus and collecting their blood after they sicken 

 with the disease. A virus pig should be in thrifty 

 condition, weighing near one hundred pounds. It 

 should not be heavily infested with parasites. 

 The dose of virus (about 2 mils) is injected in the 

 same manner as has already been described, but 

 no protective serum is given. 



