LYSINS, AGGLUTININS, PRECIPITINS, ETC. 245 



inactivated bactericidal immune serum (immune body), and comple- 

 ment in the test tube, a great excess of immune body hindered rather 

 than helped bactericidal action. As the amount of immune body in 

 the mixture was carried beyond the experimental optimum, bac- 

 tericidal action became less and less pronounced, and was finally 

 completely suspended. They explain this by assuming that free im- 

 mune body, uncombined with complement, has a greater affinity for the 

 bacterial receptor than the immune body combined with complement. 

 The complement is consequently diverted and prevented from activating 

 the amboceptor attached to the bacterial cell. Graphically, the con- 

 ditions may be illustrated as follows: 



■.^UjU^ -^y^ ^gu^ 





Fig. 63. — Neisser and Wechsbekg's Conception of Complement 



Deviation. 



The above theory of Neisser and Wechsberg is here stated simply 

 because of the wide discussion it has aroused. In the light of our present 

 knowledge concerning the relations between antigen, amboceptor, and 

 complement, their conception is obviously erroneous. 



