232 MANUAL OF BACTERIOLOGY. 



do not undergo bacteriolysis, but become fixed to the ambocep- 

 tors, and the amboceptors become united to the haptophor 

 group of the complement which are left unaffected by the 

 heating. It will thus be readily understood why bacteria 

 treated with heated immune serum are subsequently pro- 

 tected from bacteriolysis even when unheated immune serum 

 or when unheated complement is added to them. The com- 

 plementophylic haptophor of the amboceptor is in such a case 

 already occupied by the haptophors of the heated complement, 

 which has in this way become deprived of its toxophor group. 



The amboceptors found in ordinary normal serum are either 

 all alike and in this case they must possess affinity for a great 

 many different kinds of bacteria or they must differ from one 

 another; and in this case there must evidently be a great many 

 specific amboceptors, some fitted for the bacteriolysis of one 

 species of bacterium, some for others. This matter seems not 

 yet to have been settled. But it is certain that the injection 

 of an animal with certain bacteria or their products causes the 

 formation of a large number of specific amboceptors; that is to 

 say, of amboceptors having affinity only for the kind of bacteria 

 with which the animal is injected. Such injections seem not 

 to increase the amount of complement. 



Complement is found normally in the serum, that of some 

 animals possessing more than that of others. The horse ap- 

 pears to have a large amount of complement in the serum. It 

 is not yet settled whether the complement is specific that is, 

 whether the complement for one kind of immune serum can 

 unite with the amboceptors of this serum only and not with 

 the immune serum of a different sort or whether comple- 

 ments are general; though they seem for the most part not to 

 be specific. The complement in the serum of horse's blood 

 seems capable of reactivating heated immune serum of various 

 kinds. Still in some cases it would appear as if they were 

 specific. 



