1 68 



Immunity 



Bolton * has shown that normal serum may kill relatively 

 more bacteria when diluted than when undiluted. 



A 1 



II* 



Iff 



Iff 



Fig. 30. Diagram illustrating the Neisser-Wechsberg phenomenon 

 of "deviation of complement." In A 1 the three black units (c) repre- 

 sent the quantity of complement necessary for the dissolution of a bac- 

 terium, and the three white units (/>) the intermediate bodies or am- 

 boceptors through which they may act. A 2 shows these properly 

 proportioned units properly combined and anchored to the bacterial 

 cell which will be destroyed. If an excess of amboceptor units be 

 present, as is suggested in B l , the resulting combinations and the conse- 

 quent results may vary according to the differing combining affinities. 

 Thus, B 2 shows an unchanged affinity, i. e., only those amboceptors 

 unite with bacterial cells that are charged with complement. C 2 shows 

 equal affinity of the amboceptors for complement and for the bacterial 

 cell, so that charged or uncharged units attach themselves to the cell, 

 diminishing the complementary action. D 2 shows the possible result 

 when the affinity of the amboceptor for the bacterial cell is diminished 

 after charging with complement, so that though the complement and 

 amboceptor combine, there can be no destruction of the bacterium. 

 Thus, excess of the amboceptor units may "deviate the complement " 

 and prevent its action. 



It was at first hoped that some of these serums and 

 especially the bacteriolytic serums would have a wide thera- 



* "The Bacteriolytic Power of the Blood-serum of Hogs," Bull. No. 

 95 of the Bureau of Animal Industry, U. S. Dept. of Agriculture. 



