120 BACTERIOLYSINS AND HEMOLYSINS. 



which has become inactive, reactivation occurs in vitro, that is to say, the 

 bacteriolytic serum, regains its ability to dissolve bacteria. The bacterio- 

 lytic power of fresh immune serum, depends, therefore, upon the fact that it 

 contains not only bacteriolysins but also complement; the failure of old im- 

 mune serum to produce bacteriolysis is accounted for by the lack of comple- 

 ment, while its capacity for reactivation 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 bac- 

 teriolysin, 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 effected by temperatures above 

 60 C. only. 



Coficerning 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 of bacteriolysis, Bordet has recourse to certain phenom- 

 ena 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 produced 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 bacterial 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 "complementophile" group. 

 Also because of its two binding groups (receptors) the immune body itself is called ambo- 

 ceptor, 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, (Zwischen- 

 Korper, intermediary body), can complement bind itself to bacteria and dissolve them. 



