IMMUNITY. 371 



anthrax, the wandering cells of the uninocu- 

 lated animal do not take up the anthrax bacilli 

 and the same is true of some other diseases ; 

 after the protective inoculation, however, they 

 all do this, and in each individual instance the 

 protective activity thus acquired by the wan- 

 dering cell is manifested, it is claimed, only 

 against the one disease, and is therefore iso- 

 pathic or " specific." The bacteria taken up 

 by the phagocytic cells are not always digested, 

 however, and may sometimes multiply in the 

 cells and at their expense, a phenomenon that 

 is often to be seen in swine-erysipelas, leprosy 

 and tuberculosis. In the latter disease wan- 

 dering white blood-corpuscles freighted with 

 tubercle bacteria may distribute the parasites 

 over the body, and so lead to general infection. 

 But facts of this sort prove also that cells are 

 able to take up into themselves living and fully 

 virulent bacteria ; they confirm therefore the 

 contention of the phagocyte theory. 



According to Behring the tissues form the 

 anti-substances very slowly in the process of 

 "active" immunization. But this notion is 

 wholly incorrect. I have already shown that 

 the formation of anti-substances is only an in- 

 cidental and not a causal and necessary ac- 

 companiment of immunity. Immunity may be 

 brought about and yet these antagonistic sub- 



