402 DISEASES OF SWINE 



tion, as we are then certain the virus enters the body, and are sure 

 of getting a permanent immunity. 



From these examples we are able to draw a few rules for use 

 of the single or serum-alone method of treatment: 



(1) This method of treatment should be used in all herds where 

 the disease is already present, as shown by the presence of sick ani- 

 mals, the death of one or more hogs, with the usual changes produced 

 by hog-cholera to be found when the carcass is opened up, or by 

 the presence of a number of animals in the herd showing a high 

 temperature. In case of a herd that is located close to another 

 herd in which cholera is present, if the animals show a temperature 

 of above 105° F. it is pretty certain that they are already being 

 attacked by the germs of cholera, and are well along in the incuba- 

 tion period of the disease. 



These animals with a high temperature already have the germs 

 of the disease present in their body, and it is not necessary to inject 

 any more of them, so the single method of treatment is to be here 

 given. Those that show normal temperatures in the same herd 

 had better be given the simultaneous treatment. 



(2) Animals that are about to be placed in pens that have recently 

 been the seat of an outbreak of hog-cholera should either be given 

 double treatment on the farm from which they are to be moved, or 

 they can be given single treatment and placed immediately in the 

 infected pens. The better method is to give the double treatment on 

 the farm from which they are to be purchased, wait three weeks for 

 the development of the complete effects of the treatment, and then 

 bring them home and place in the infected feed lots. If the double 

 treatment has been properly given, there will be absolutely no 

 danger in placing these animals in the feed lots where the other 

 animals have recently died, or even where there may be sick ani- 

 mals at the time. 



(3) There is another class of cases where the serum alone might 

 be given. This is in the case of very young pigs. The double 

 treatment, while it has no bad effects on these little fellows, does 

 not always give a permanent immunity, and it is considered ad- 

 visable by some men to give the single treatment to these pigs", and 

 follow it about six weeks later with the double method of treat- 

 ment. This is especially advisable if there be an outbreak of 



