METHODS OF USING ANTI-HOG-CHOLERA SEBUM 153 



3. When the treated herd cannot be properly 

 segregated. 



4. For sucking pigs as a routine measure. (In- 

 formation still incomplete on this point.) 



5. For sows about to farrow, or for those nurs- 

 ing young litters. 



6. In badly infected herds. 



7. In animals with low resistance due to ship- 

 ping, weaning, castrating and other influences. 



8. In all circumstances in which serum alone 

 will be equally effective. 



Follow-up treatment. This consists of giving 

 serum alone and following it in a few weeks, usu- 

 ally less than four, with simultaneous treatment. 

 It has been called "double treatment " by some, 

 but according to usage which has now become 

 fixed, the terms " double treatment" and "simul- 

 taneous treatment " are applied interchangeably 

 to serum-virus administration. It therefore seems 

 desirable to apply to serum alone followed by 

 simultaneous treatment, the separate, distinct and 

 self-explanatory term, "follow-up treatment. " 



Follow-up vaccination is safer than simultane- 

 ous treatment, it can be applied under circum- 

 stances which practically forbid the use of the 

 latter method, and the final result is the same 

 a permanent immunity is established. There are 

 those who believe that the passive immunity pro- 

 duced by the dose of serum alone prevents the re- 



