400 INFECTION AND RESISTANCE 



over intracellular enzymes quite capable of substituting functionally 

 for complement. 



It seems necessary to add that, however one may look upon this, 

 it does not affect the importance of the so-called "anaphylatoxins" 

 and similar toxic protein cleavage products in the toxemia of infec- 

 tious disease or in general pathology. 



Now, as to the identification of the anaphylactic antibody with 

 some one of the well-known antibodies, the assumption is that in 

 cellular anaphylaxis (as in the corpuscle experiments of Friedemann 

 and in the bacterial experiments of Friedberger and others) the 

 so-called sensitizer or amboceptor is to be held responsible. This 

 seems reasonable, and there is much evidence that seems to favor 

 such a view. 



In the case of serum anaphylaxis extensive work has been done 

 to show a parallelism between the anaphylactic antibody and the 

 precipitins. This we have seen principally in the experiments of 

 Doerr and Euss, and those of Friedberger. 



The problem becomes a complicated one when we attempt then 

 to define the nature of the precipitins and their relation to the anti- 

 bodies hypothetically advanced as "albuminolysins" by Gengou. 

 Without going into this point extensively at present, it may be per- 

 mitted to refer the reader to the chapters on alexin fixation and 

 precipitins, and to reiterate the writer's 46 own opinion, which is 

 that much reasonable evidence points to the fact that the so-called 

 precipitins are in truth protein-sensitizers, identical in structure and 

 function with the sensitizers or amboceptors of cytolytic processes. 

 The fact that precipitation occurs when these antibodies are added 

 to the homologous dissolved antigen is merely a secondary colloidal 

 phenomenon; antigen and antibody react, forming a complex which 

 is then amenable to the action of alexin. Being colloidal ki nature, 

 and mixed under quantitative and other conditions which favor floc- 

 culation, they precipitate. This point of view, then, identifies the 

 so-called precipitins with the protein-sensitizers or albuminolysins 

 first hypothetically suggested by Gengou. It leads necessarily 

 to the conception that in cytolysis as well as proteolysis, in fact, 

 in all reactions in which antigen is sensitized to the action of 

 alexin, there is functionally but one variety of antibody the sen- 

 sitizer precipitation and agglutination being incidental physical 

 phenomena not dependent upon special antibodies as heretofore 

 supposed. 



In this sense, then, the "precipitins" or albuminolysins may be 

 regarded as identical with the anaphylactic antibody. 



That animals in whose circulation antigen and antibody are 

 simultaneously present do not suffer from symptoms of anaphylaxis 

 46 Zinsser. Jour. Exp. Med., Vol. 15, 1912, and Vol. 18, 1913. 



