EXPERIMENT STATION BULLETINS. 407 



against the filtered virus and an 18 lb. pig in 15 c.c. dose against the un- 

 filtered virus. TTiis serum also agglutinated B. cholerae suis when di- 

 luted 1-8,000. 



5. It was found that the Dorset-Niles serum is more potent against 

 the filtered virus than against the unfiltered virus. 



6. The mixing of the Dorset-Niles serum and hog cholera virus in 

 vitro and incubating 21^ to 3 hours does not seem to lessen the virulence 

 of the virus. There is no indication that mixing the serum and virus 

 in vitro has any advantage over the serum-simultaneous method of in- 

 jecting these agents for immunizing jtigs against hog cholera. 



