CLINICAL EVIDENCE OF VALUE OF SERUM 459 



home farm the disease broke out there, infection having been car- 

 ried to it in some manner. The disease broke out first among 

 the untreated checks, and 5 of the 10 untreated animals that re- 

 mained on the farm died of the disease in a few days after it made 

 its appearance. 



Of the treated pigs which received the serum alone, one of the 

 4 30-pound pigs and 5 of the 10 sucking pigs died of the disease. 



The untreated sucking pigs which were left as checks, and some 

 other sucking pigs that were born after the treatment had been 

 given, all took the disease and died, with the exception of 2. 



The results obtained in this herd are, indeed, most instructive, 

 and give us a large number of practical lessons in hog-cholera and 

 methods of handling the disease. 



In the first place, it shows that a herd of hogs may remain 

 healthy even in an infected district for a long period of time if there 

 is no direct communication with other farms, by means of which the 

 disease-producing virus may be brought upon the premises. 



In this herd a large part of the animals received the double 

 method of treatment, some of them received the serum alone, and 

 others were left untreated. Yet we have no outbreak of the disease 

 in this herd which could be laid to the giving of the double treat- 

 ment. This is another example of the perfect safety with which 

 the double method of treatment may be given. The danger of 

 infecting the premises or producing the disease in other untreated 

 animals which may be left on the place or afterward brought into 

 the feed lots is largely an imaginary one. Where such a result does 

 follow, it is either due to the fact that the serum used in giving the 

 treatment was worthless or else is due to the fact that the man who 

 injected the virus, and was responsible for handling it, was care- 

 less and allowed it to become scattered about on the ground, where 

 it could be picked up by other animals or tracked away on the shoes 

 of a neighbor to his herd. 



The disease which broke out in the home herd was no doubt 

 due to the carrying of infection from the neighbor's feed lot by the 

 men who helped to move the hogs that were taken to this diseased 

 farm for experimental purposes. This gives a good example of 

 the extreme care which must be used in going into a feed lot or on 

 a farm where hog-cholera may be present. It is very easy, indeed, 



