332 BACTERIOLOGY. 



with contribute to the blood new defensive sub- 

 stances. 



The " specificity " of protective inoculation 

 with the anti-substances depends therefore only 

 apparently, just as in the case of protective 

 inoculation with living parasites and with 

 metabolic products, upon the " specificity " 

 of the microbes. 



It would seem, accordingly, that the " speci- 

 fic anti-substances " of the blood resulting from 

 " specific " immunization and establishment of 

 tolerance of poisons are substances derived 

 from " specific " disease germs, worked over, 

 however, in a peculiar way and made active by 

 u specific " body cells, or brought into union 

 with an active proteid of the body to form a 

 new and active substance. Emmerich has 

 suggested the name " immunizing proteids " 

 for these hypothetical substances. 



Do the Antitoxins Bring About Specific 

 Immunity ? 



The fact that new bodies of this sort are 

 formed, that is to say that new qualities ap- 

 pear in the organism, does not necessarily 

 prove that these substances are the ones that 

 exert the specific protective effect. I have al- 

 ready urged this point, but have been unable 



