THE PRODUCTION OF ACTIVE IMMUNITY 149 



amount of tolerance for the intracellular poison of the 

 colon bacillus as represented by the toxic part. In the 

 case of animals treated with the residue, however, no 

 tolerance for the poison contained within the colon bacillus 

 has been developed. If now the process which takes place 

 in both instances is a bacteriolytic one, it results that in the 

 case of the animal immunized with the toxic group the 

 effects of the poison contained within the bacterial cell and 

 liberated upon its disintegration will not become manifest 



FIG. 9 



The temperature curve of an animal immunized with the colon residue and 

 afterward inoculated with twice the lethal dose of the living culture. 



until a sufficient amount of poison has been set free to 

 overcome the tolerance which the animal has attained 

 during the process of immunization. In the case of the 

 animal immunized with the residue there is no tolerance 

 to be overcome other than that which is present in all 

 animals, and the effects of the poison liberated through 

 bacteriolysis become apparent sooner and to a more marked 

 extent. Again, the fact that bacteriolysis may occur more 

 rapidly in the case of residue pigs than in those immunized 

 with the toxic group might explain in part the difference 



