234 



MANUAL OF BACTERIOLOGY. 



amboceptors attached to complements, k. Bacteriolysis is not 

 possible in such a condition, because the complements have 

 been diverted from the amboceptors which are attached to the 

 bacteria. Bacteriolysis can take place only when the comple- 

 ment becomes attached to the bacterium through the medium 

 of the amboceptor. 



Fig. 58 is meant to show the same serum diluted with an 

 equal amount of salt solution. In this case, with the same 

 number of bacteria added, it is evident that one-half of them 

 would be killed, as is indicated by the combination between 



bacteria, amboceptor, and 

 complement in Fig. 56. The 

 other half of the bacteria 

 would evidently escape, the 

 complement being diverted by 

 the free amboceptor, as shown 

 by Figs. 57 and 58. 



The conditions under which 

 bacteriolysis would take place 

 and those under which no bac- 

 teriolysis would take place in 

 any given serum, may be sum- 

 marized as follows : 

 I.. Complete bacteriolysis could take place only where there 

 were no free amboceptors and where there were at the same 

 time a number of amboceptor-complements equal to or greater 

 than the number of bacteria introduced. 



On dilution in a serum of this kind there would be a loss of 

 bacteriolytic power in proportion to the degree of dilution if the 

 amboceptor-complements were exactly equal in number to the 

 bacteria introduced. If there were more amboceptor-com- 

 plements originally in the undiluted serum than the bacteria 

 introduced, then on dilution there would be relatively more 

 bacteria destroyed. If the excess of amboceptor-complements 



I 



Fig. 58. — Partial bacteriolysis and 

 partial diversion of complement in 

 diluted immune serum. 



