144 HOG CHOLERA 



ally, survive the ordeal, but exceptions prove the 

 rule and embarrass the veterinarian. In several 

 instances we have known men to castrate pigs dur- 

 ing the week following simultaneous treatment. 

 In some of these a number of the castrated pigs 

 died, while the female pigs, which remained as 

 checks, survived, thus furnishing excellent but 

 rather involuntary and costly experiments. Pigs 

 are best castrated as sucklings, but in any event, 

 it is well to separate castrating and simultaneous 

 treatment at least two or three weeks. 



Ascarids may exist in the intestine in large 

 numbers without appreciably lowering the resist- 

 ance of simultaneously treated pigs, but if the 

 parasites enter and occlude the gall duct, the in- 

 fested hog shows a remarkable intolerance for 

 virus. We have observed this intolerance again 

 and again both in test pigs and in the field. Prac- 

 titioners cannot always avoid trouble due to as- 

 carids, for granting that they know the parasites 

 exist in a herd, it is not always possible to deter- 

 mine their location in the individual, and often 

 it is not safe to delay treatment. Severe jaundice 

 in pigs is usually due to ascarids in the gall-duct, 

 and its presence, easily observed in white pigs, 

 should suggest caution. 



Overfeeding is injurious to pigs passing through 

 the reaction following simultaneous treatment. 

 Any one who has observed serum tests knows 



