PRINCIPLES OF BACTERIOLYSIS 133 



vitro, that is to say, the bacteriolytic serum regains its ability to dissolve 

 bacteria. The bacteriolytic power of fresh immune serum, depends, 

 therefore, upon the fact that it contains not only bacteriolysins but also 

 complement; the failure of old immune serum to produce bacteriolysis 

 is accounted for by the lack of complement, while its capacity for reac- 

 tivation is explained by the still present bacteriolysins. 



As the above-described experiments indicate, bacteriolysis is a complex 

 process, which is produced by the interaction of two substances; one, the 

 bacteriolysin, is formed through an immunizing process, and accordingly is 

 a specific antibody of great stability, while the other, the complement, is a 

 normal non-specific and very labile serum substance. 



The stability of the immune bacteriolysin is evident in its resistance to 

 heat, whereas the complement is thermolabile. If freshly drawn immune 

 serum is heated to 56 C. for one-half hour, the complement is, as a 

 rule, rendered ineffective, while the bacteriolysin is not in any way in- 

 jured; it retains its specificity, and the degree of its affinity to antigen 

 remains unchanged. Bacteriolysins are interfered with by temperatures 

 above 60 C. only. 



Concerning the finer mechanism of bacteriolysis there are two opposing views, that 

 of Bordet and of Ehrlich. Without considering too closely the remarkable researches 

 of these two investigators, the synonyms for bacteriolytic antibodies usually found in 

 the literature will be reviewed. 



In attempting an explanation for bacteriolysis, Bordet has recourse to certain phe- 

 nomena in staining technique. There are some substances which can be stained only 

 when prepared in a definite way by means of another substance, a so-called mordant 

 ("Beize") which itself is not a stain. According to Bordet, the specific substance pro- 

 duced by immunization represents a kind of mordant which "sensitizes" the bacteria 

 to the action of the second normal non-specific substance; the latter is really the active 

 agent in causing the dissolution of bacteria and is called by Bordet "alexin" an older 

 term used by Buchner in contradistinction to "substance sensibilitrice." 



Ehrlich, on the other hand, advocates a more chemical conception of the essential 

 process of bacteriolysis. He believes that the substance formed by immunization, which, 

 for the sake of brevity, is called the immune body, is characterized primarily by the 

 fact that it has two binding groups. One of these has a chemical affinity for the bac- 

 terial cell and is, therefore, known as the "cytophile group," the other is characterized 

 by its binding affinity for complement and is, therefore, known as the " complemento- 

 phile" group. Also because of its two binding groups (receptors) the immune body 

 itself is called amboceptor, that is, double receptor. 



Thus, according to Ehrlich, bacteriolysis takes place in the following way : The cyto- 

 phile group of the amboceptor, which is strictly specific for its antigen, attaches itself 

 to the antigen, for instance the cholera vibrio; while the complementophile group binds 

 the complement. The complement must be regarded as a sort of digesting (proteolytic) 

 ferment. Although it is always present in normal serum, it is not effective, because 

 bacteria have no affinity for it. Only through the medium of the amboceptor (Zwis- 

 chen-Korper, intermediary body) , can complement bind itself to bacteria and dissolve 

 them. 



