CLINICAL EVIDENCE OF VALUE OF SERUM 437 



70 pounds, and including 2 sick animals, were left untreated as 

 checks. The remainder of the herd, consisting of 67 in all, were 

 treated, being given the serum-simultaneous injection. Each 

 animal received 20 c.c. of serum and 2 c.c. of virulent blood. 



The results of this experiment are quite interesting, in the fact 

 that they give us considerable information showing that injection 

 of virus with proper dose of serum is not injurious even in the 

 presence of visible infection. 



Of the 12 shoats which were left untreated, 10 became sick, 

 exhibiting the usual symptoms of hog-cholera. Of these 10, all 

 but 2 died. The 2 that recovered never made a full recovery, 

 and always remained more or less stunted and unthrifty. Of 

 the 67 animals that were treated, only 3 sickened and died. The 

 remaining 64 animals remained well and thrifty. 



The heavy loss among the shoats left untreated as checks 

 goes to show that the disease was of a most virulent type, and 

 but for the prompt use of the serum almost the entire herd would 

 have been wiped out. 



One of the interesting points to note here is the fact that no 

 harm was done even by injection of virus in the presence of con- 

 tact infection. The serum-simultaneous method of treatment is 

 practically entirely harmless if used by those who understand 

 their business and use it with due regard for its potency and pos- 

 sibilities for harm. The 3 animals that died were undoubtedly 

 already severely infected at the time the treatment was given, 

 and had already passed well along in the incubation period. 

 However, the injection of the virus used undoubtedly had nothing 

 whatever to do with producing the death of these 3 animals. 



Again in this instance we see an example of the stunted con- 

 dition which usually remains in animals which naturally contract 

 the disease and recover. 



We also have in this herd an example of 2 animals which 

 apparently possessed a natural immunity, as 2 of the untreated 

 checks did not develop any symptoms of cholera. 



Herd number seven of this experiment was located in the 

 northwest quarter of Section 27, Grant Township, Story County, 

 Iowa. This herd was first seen on October 7, 1907. At the 

 time of this first visit these hogs were already in a very seri- 



