228 



ORIENTAL PLAGUE 



CHAP. 



The blood serum of both animals was tested (dilutions 

 1 : 20 and 1 : 10 in each instance) : — 



From this it appears that neither in the rabbit nor 

 in the guinea-pig was there any agglutinin formed after 

 repeated injection of the filtrate alone of Haffkine's 

 prophylactic. It was altogether unexpected that half- 

 grown rabbits should, after receiving a total of 100 cc. of 

 this filtrate, yield blood serum which showed no sign of 

 agglutinin even in dilution of 1 in 10. 



IV. — Experiments with Blood Serum op Rats 



I have already mentioned that rats which had passed 

 through the disease (rats which had first been prepared by 





