THE NATURE OF TOXIN 



107 



TABLE 3 



Second growp oj rabbits, sixty days later 



1. Rabbit injected organisms. 



2. Rabbit injected organisms. 



3. Rabbit injected organisms. 



4. Rabbit injected toxin 



5. Rabbit injected toxin 



6. Normal rabbit 



7. Control, no serum 



No. 3 



+ 

 + 



+ 



+ + 



In tables 1, 2, and 3, H — \- = no hemolysis, complete inhibition; + = partial 

 hemolysis; — = complete hemolysis, no inhibition. 



From these tests it appeared that artificial antigen no. 2 gave 

 results in closest agreement with the control diphtheria germ 

 suspension antigen. It was accordingly employed in the suc- 

 ceeding work. We do not agree with the statement of A. 

 Besson^ to the effect that animals immunized with toxin show no 

 immune bodies in their serums. 



Agglutination and precipitation experiments were not made 

 with these serums or this antigen, nor was any attempt made, 

 for reasons mentioned earlier, to immunize animals with the 

 artificial antigen, such reactions being shown better with the 

 B. megatherium. 



THE NATURE OF DIPHTHERIA TOXIN 



The toxic broth as it comes from the filters is alkahne, having 

 a pH varying from 8.0 to 8.33. An experiment of Connell's 

 showed that the increased alkalinity might be due to the am- 

 monia, of which there was found 34 mgm. against 14 mgm. in 

 fresh broth. We had also shown that, among other changes, 

 the broth had become richer in fats, or salts of fatty acids, and 

 that these corresponded with those obtained from the bodies of 

 the germs themselves. 



« Pract. Bact., 1913, p. 269. 



