EXPERIMENT STATION BULLETINS. 415 



This summary shows the tendency toward an increase in agglutina- 

 tive power of blood from heavier hogs in addition to demonstrating the 

 increased agglutinative power as a result of increased dose of virus. 



It might be supposed, with reason, that the source of the virus used 

 for treating the pigs would influence the production of agglutinins 

 in the treated pig. It is a point having little force in this connection, 

 since all the virus used (except that on Expt. 291) had the same 

 source, viz. the "Ames virus." The only difference in these virus de- 

 pends upon the variation in their passage through pigs and in their age. 



In all these cases the sample was secured after the pig died from 

 the disease, or was killed. The number of days the pig lived after in- 

 jection of the virus seems to bear no constant relation to the agglutina- 

 tive power of the pig's blood serum. Except in those cases where the 

 pig died, it may be assumed that the pig was killed at the height of 

 the disease. We have no data on the rate of increase of the agglutinin 

 after treatment of individual pigs. We learn very little by comparing 

 the reaction of the blood of pigs that died with those that were killed. 



REACTIONS WITH THE BLOOD OF PIGS TREATED WITH '^''mIXED SERUM." 



Table III shows the data connected with the testing of blood from 

 49 pigs treated simultaneously with hog cholera seiiim and virus. The 

 important features of this table in addition to the agglutination re- 



