METHODS OF USING ANTI-HOG-CHOLERA SERUM 151 



to come in contact with vaccinated ones during 

 the four weeks following treatment. It is some- 

 times difficult to mention these things, without 

 causing the dangers to be exaggerated in a client 's 

 mind, and some breeders will decide not to take 

 risks which they would readily assume could they 

 know how slight they really are. Nevertheless a 

 veterinarian's first duty is to protect his client, 

 and he must protect himself if he is to remain in 

 practice. The man who glibly advises that there 

 is "no danger " following his vaccinating is not 

 doing either. 

 Summary of action of simultaneous treatment. 



1. Produces an active permanent immunity in 

 all hogs more than twelve weeks of age. 



2. Produces active immunity in some suckling 

 pigs, passive immunity in others. 



3. Usually produces a very mild reaction begin- 

 ning about five days following treatment, and last- 

 ing less than seven days. 



4. In hogs with low resistance, 1 sometimes pro- 

 duces a severe reaction which exceptionally ter- 

 minates in death. 



5. Causes some hogs to eliminate hog cholera 

 virus in their excretions during the time the reac- 

 tion is in progress. 



1 The terms ' ' resistance ' ' and ' ' condition ' ' should not be con- 

 fused. The former, as used here, applies to the state of the ani- 

 mal's natural defenses against disease, and is determined by the 

 history, as well as by the appearance of the animal. "Condition" 



