196 COLLECTED STUDIES IN IMMUNITY. 



character, in a recent work especially designed to refute the plural- 

 istic view of the complements, has published a series of experiments, 

 which in his opinion necessarily point to a simple alexin. Bordet's 

 argument is based on the discovery of the interesting fact that blood 

 corpuscles or bacteria treated with an inactive immune serum specific 

 for themselves were able to deprive a normal active serum of all 

 its complement activity. 



Bordet sensitized blood corpuscles with appropriate amboceptors, 

 and then exposed them to the action of a freshly drawn normal serum. 

 If now he waited for the occurrence of haemolysis and then added 

 sensitized cells, bacteria, or blood corpuscles of different species, 

 they remained totally unchanged, although the serum that had been 

 used as complement was capable in its original condition of destroy- 

 ing these also. When fresh serum was first brought into contact 

 with sensitized bacteria, similar results were obtained. The blood 

 corpuscles subsequently added did not then undergo haemolysis. 



// such an action on one of the sensitive substrata has once taken 

 place, the active sera, as a rule, are deprived of all their complement 

 functions, from which Bordet concludes that the destruction of the 

 most varied elements by one and the same serum must be due to 

 a single complement. 



It must be acknowledged that these experiments, which we have 

 been able to verify in numerous cases, at first sight seem to sup- 

 port Bordet's view. If one assumes that a certain serum A, which 

 is capable of complementing two different bodies B and C, one bac- 

 tericidal and the other hsemolytic, contains only a single comple- 

 ment, Bordet's results would then most readily be explained by 

 assuming that the two immune bodies are identical in their com- 

 plementophile groups. In that case, of course, owing to the previous 

 exercise of the one function, the available complement will have 

 been used up, so that nothing is left for the exercise of its second 

 function. But a closer examination shows us that this view is an 

 artificial one, and does not correspond to the facts observed. For if 

 it be assumed that this particular serum A contains two different 

 complements, both of which can be absorbed by the amboceptors B 

 and C, Bordet's experiment will find an entirely different explana- 

 tion. Now previous investigations l have shown that the artifi- 

 cially developed immune sera are not of simple constitution, but 

 contain a number of different amboceptors possessing different com- 



1 Ehrlich and Morgenroth, p. 56. 



