82 HOG CHOLEEA 



virus pigs to calves so as to guard against foot- 

 and-mouth disease, are just a few of the acces- 

 sories that circumstance must include or elimin- 

 ate. 



Further detail in regard to equipment cannot be 

 profitably discussed here. In all these things sim- 

 plicity, cleanliness, convenience and low upkeep 

 cost are the chief considerations. Good equip- 

 ment invites clean operations, but in the last anal- 

 ysis the quality of the finished product is not de- 

 termined by equipment. A careless operator will 

 contaminate serum in spite of every convenience ; 

 a careful one will produce clean products under 

 adverse working conditions. 



'Principle governing serum production. When 

 a hog contracts cholera and recovers, or when it 

 receives simultaneously hog cholera virus and 

 protective serum, it is thereafter immune to the 

 disease. The body cells, in self-defense, have elab- 

 orated substances, termed antibodies, which neu- 

 tralize the effects of all hog cholera virus subse- 

 quently introduced into the system. In the ordi- 

 nary immune hog these antibodies protect against 

 any quantity of cholera virus to which the animal 

 may be exposed, but they do not exist in sufficient 

 concentration so that the blood may be used to 

 protect other animals. Antibody elaboration 

 must be further stimulated, and this is done by 

 giving the immune an enormous intravenous dose 



