160 HOG CHOLERA 



would have us believe, different according to the 

 section of the country in which we chance to find 

 it. The differences we observe in various parts of 

 the country are due principally to prevailing sec- 

 ondary invaders, as well as to variation in viru- 

 lence of the hog cholera virus itself, for they are 

 observed also in comparing individual herds or 

 outbreaks in any one section. 



While we must accept all these variations and 

 allow for them, the underlying principles em- 

 ployed in handling hog cholera remain unchanged, 

 and it is desirable and necessary in a treatise of 

 this kind to suggest definite working plans, leaving 

 the reader to alter or supply detail as individual 

 cases warrant. We are moved to do this because 

 we have seen young graduates of veterinary col- 

 leges who had had good instruction and whose 

 technique in administering serum left little to be 

 desired we have seen some of these men practi- 

 cally helpless in the presence of outbreaks of 

 cholera which presented disturbing but not un- 

 usual features. Likewise men who are accus- 

 tomed to the routine of vaccinating thousands of 

 stockyard hogs are sometimes confused when they 

 are called on to accept the conditions they meet 

 on the average farm, to prescribe treatment for 

 a mixed lot of swine, and guide the breeder away 

 from future trouble. Mere knowledge of how to 

 vaccinate hogs does not equip one to handle hog 



