PREPARATION OF ANTI-HOG-CHOLERA SERUM 89 



sions do not cause rejection. Here, we believe, a 

 very rigid interpretation is advisable, and in all 

 cases which admit doubt the pigs should be re- 

 jected. 



Pigs that show enormously enlarged, dark, 

 pulpy spleens as well as those that bleed scantily 

 and yield very dark blood do not produce satisfac- 

 tory virus. The tendency in both cases is for the 

 blood to defibrinate imperfectly and when it is 

 mixed with good virus the entire lot may be 

 ruined. 



In the routine autopsy the skin, and all of the 

 thoracic and abdominal viscera are examined, as 

 well as the submaxillary and superficial inguinal 

 lymph glands. In case of doubt, due to slight le- 

 sions, the mucosa of the larynx and popliteal 

 lymph nodes should be included. 



Disposal of carcass. Virus pig carcasses may 

 be burned or rendered as circumstances direct. 



The Hyperimmune 



The immunes which are to be hyperimmunized 

 and later yield serum should be carefully selected. 

 The longer they have been immune to hog cholera, 

 the better. They should be hearty feeders, in 

 moderate flesh, and always strong and active. 

 The ears should be moderately large, but thin and 

 well veined, and the tail at least of average length 

 so as to permit the required number of bleedings. 



