NATURE OF HEMOLYSINS 365 



At higher temperatures these relations were more difficult to demon- 

 strate, as hemolysis occurs rapidly, but by leaving the cells and serum in 

 contact for short periods of time, centrifuging rapidly, and testing the 

 corpuscles and supernatant fluid in the same manner, similar relations 

 were found to exist. 



These experiments led Ehrlich to formulate the theory that comple- 

 ment will unite only with the antibody and not with the red corpuscles, 

 but that it acts upon the corpuscles when united. indirectly by means of 

 the antibody. As will be pointed out further on, this view is in direct 

 opposition to that of Bordet, who does not accept this interpretation, 

 but believes that the complement acts directly upon /the corpuscles. 



Ehrlich, therefore, conceived the antibody as being in the nature of 

 an amboceptor or of an interbody between an antigen and complement, 

 with two combining arms one the cytophile haptophore for union with 

 the cell, and the second, the complementophile haptophore for union with 

 complement. The amboceptor is unable in itself to injure the cell, but 

 preserves its importance in being the only and specific means by which 

 the ferment or complement can attack the cell and cause its destruction. 



The process of specific serum hemolysis is therefore supposed to be 

 as follows: In fresh immune serum containing both amboceptors and 

 complement, or in a mixture of old or heated immune serum and fresh 

 normal serum (i. e., of amboceptor and complement), the two substances 

 occur independently of each other. When the corpuscles corresponding 

 to the amboceptor are added, the amboceptor unites with these and the 

 complement unites with the amboceptor, the amboceptor, therefore, 

 standing midway between corpuscles and complement. When these 

 unions have taken place, hemolysis will result. The amboceptor has a 

 greater affinity for the corpuscles than the complement has for the am- 

 boceptor, and will unite with the cells at a low temperature, whereas the 

 complement unites with the amboceptor only very slowly at low tem- 

 peratures. Body temperature favors a quicker union of both, and 

 especially that of complement with amboceptor. Hemolysis, therefore, 

 may occur at low temperatures, but is hastened by higher temperatures, 

 and occurs best at 37 C. 



As stated in a previous chapter, Ehrlich believes that a great many 

 complements exist in normal serums, which view is in direct opposition 

 to the " Unitarian theory" of Bordet, which holds that the one alexin or 

 complement will act with any sensitizer or amboceptor. Of the large 

 number of complements, each is especially adapted for the solution of 

 one or more varieties of cells, which it can dissolve in conjunction with a 



