RESEARCHES ON CERTAIN PROBLEMS OF PLAGUE IMMUNITY 1 7 



TABLE VII.— Toxin 10. 



14 days after previous Test on Mice of 15 grammes weight. 

 Intraperitoneal injection. — - 



Second Test (contimied). 



TABLE VIII.— Toxin 10. 



Testing Toxicity on Rats. 

 Subcutaneous injection. 



It is interesting to note that rats and mice offer much less resistance 

 to the action of plague toxin than do rabbits and guinea-pigs. That the 

 latter animals have the more powerful defence is shown by the experi- 

 mental results given in Tables IX. and X. 



(127) 



