PHAGOCYHC AND SIDE-CHAIN THEORIES 



157 



unite corpuscles of the animal used in the injection and only these cells, 

 with a complement, and thus bring about their solution or lysis. If 

 certain bacteria (e. g., the cholera bacillus) are injected into an animal, 

 specific bacteriolysins (bacteriolytic amboceptors) will be produced. 

 Similarly, specific amboceptors are produced during the course of in- 

 fections with typhoid bacilli, and are largely instrumental in combating 

 and overcoming this infection. It is important to remember, however, 

 that although these amboceptors probably prepare their antigens for 



FIG. 42. FORMATION OF CYTOLYSINS (HEMOLYSENS, BACTERIOLYSINS, CYTOTOXINS). 



The central white area represents a molecule of a cell; the shaded portion repre- 

 sents the cell itself; the surrounding area represents the body-fluids about the cell. 



R, Receptor of the molecule (third order)'; R 2 , overproduction of receptors, which 

 are being cast off; A, a cast-off receptor which now constitutes the antibody or am- 

 boceptor; C, molecule of complement free hi the body-cells and body-fluids; A 2 A 4 , 

 amboceptors in combination with molecules of a cell (antigen) and a complement; 

 A 3 , an amboceptor in combination with a molecule of a cell. The cell (antigen) is 

 now said to be sensitized. Lysis does not occur because a complement is not united. 



lysis, or, in the meaning of Bordet, " sensitize" them, they are not in 

 themselves lytic, final solution of the antigen being accomplished by the 

 ferment-like substance the complement. 



COMPATIBILITY OF THE PHAGOCYTIC AND SIDE-CHAIN THEORIES 



When we seek to compare the theory of Metchnikoff with that of 

 Ehrlich, we find that they differ only in minor details, the fundamental 



