CLINICAL EVIDENCE OF VALUE OF SERUM 457 



vaded the same feed lot in which they were located and destroyed 

 the untreated animals. 



If a hog is properly immunized by means of the serum-virus 

 combination treatment he is protected for all time against the 

 disease, and will not be made sick by hog-cholera, no matter how 

 much or how often he may be exposed. As in the case of the herd 

 just described, the disease may be present in the same feed lot 

 in which the treated animals are kept, and untreated animals 

 may die all around them, but the animals which have been given 

 the simultaneous method remain healthy. This holds true no 

 matter how long after the giving of the treatment they may be 

 exposed. 



It can be easily seen from this that the double method is the 

 method of choice in the handling of herds that have been exposed 

 to the disease, or which are located in a neighborhood where the 

 disease is present. It is by the use of this method of treatment 

 that we will be able to prevent the spread of the disease in a 

 community and save thousands of hogs in every county in the 

 United States. 



If all the animals in this herd had been treated the disease would 

 never had made its appearance in the herd at all. Of course, these 

 herds were injected for experimental purposes, and it was neces- 

 sary to leave some animals untreated in order that the men in 

 charge of the work might have an opportunity to draw conclu- 

 sions as to just what the treatment would do. In actual field work, 

 of course, all the animals in the herd should receive the treatment. 



The only danger in the giving of the virus treatment hes in the 

 use of a poor grade of serum. The sreum used must be of tested 

 quality. Be certain of your serum, and then, by using ordinary 

 judgment in handling the dosage, only the best of results will 

 follow. 



Herd Number Eighteen. — The eighteenth herd treated in this 

 series of experiments was located in the northeast quarter of Section 

 3, Union Township. The herd was located in a neighborhood in 

 which the disease was widely scattered, and this farm was sur- 

 rounded by a number of disease-infected farms. 



At the time of treatment, which was on October 17, 1907, the 

 animals were all apparently well. The herd was of the usual mixed 



