286 COLLECTED STUDIES IN IMMUNITY. 



human serum contains no anticytase whatever, and when, as in the 

 above combination, human blood -f specific ambocep tor + guinea-pig 

 serum, this serum exerts a protective action, it follows by exclusion 

 that this action is due to an antiamboceptor. 



The fundamental error in this method of proof lies, as already 

 mentioned, in the assumption of a simple cytase, which cytase, more- 

 over, is able by itself to effect haemolysis. As a matter of fact, how- 

 ever, solution of the blood-cells by guinea-pig serum is brought 

 about only by this, that the blood-cells combine with a normal am- 

 boceptor present in the blood serum, and that this thereupon anchors 

 the complement (cytase) which effects solution. If the complement 

 in itself is conceived as a single substance, one could conclude from 

 the fact that the human serum does not prevent this normal haemoly- 

 sis that the human serum contains neither an antibody against the 

 normal ambocep tor nor against "the complement." In reality, 

 however, "the complement" is made up of numerous partial com- 

 plements, one or another of which is dominant for the completion 

 of particular ambocep tors, be these haemolytic or bacteriolytic. This 

 theory of dominant complements has been firmly established by 

 Ehrlich and Marshall. 1 



It has already been proven for anticomplementary sera that such 

 a serum neutralizes only part of the complements of a second serum, 

 not all. Marshall and Morgenroth 2 have shown that the anticom- 

 plement of a human ascitic fluid prevents the complementing action 

 of guinea-pig serum for one haemolytic amboceptor leaving that of 

 another intact. 



Now Besredka showed that human serum does not prevent the 

 normal haemolytic action of a certain serum, although it acts anti- 

 haemolytically when this is used as complement for an amboceptor 

 produced by immunization. The only conclusion to be drawn from 

 this is that the human serum contains no anticomplement which 

 acts against the complement dominant in the case of the normal 

 haemolysis. This, of course, does not prevent the same serum from 

 acting on other partial complements which are dominant in other 

 cases. We see, therefore, that Besredka J s entire method of proof 

 lacks a firm basis. 



It is further to be remembered that such questions are to be de- 



1 See page 226 et seq. 2 See page 222. 



