288 COLLECTED STUDIES IN IMMUNITY. 



Finally, the fact that at times a small part of the antihsemolytic 

 action (as in our experiments with a human exudate and ox blood) 

 is due to an antiamboceptor, removes the basis for Besredka's gen- 

 eralization that a normally present antiamboceptor always protects 

 only its own blood-cells. 



From all this it follows that the part believed to be played by the 

 antiamboceptors of human and animal body fluids in the prevention 

 of haemolysis is materially decreasing in favor of the part taken by 

 the anticomplement. There is no doubt at all that antiamboceptors 

 exist in normal serum; this was first proven some time ago by Ehr- 

 lich and Morgenroth, 1 and also by P. Miiller. 2 These antiambocep- 

 tors do not, however, occur regularly, as was also pointed out at 

 that time. 



Our analysis therefore shows that since the fundamental fact 

 does not apply, the extensive theoretical conclusions drawn by Bes- 

 redka from the exclusive protection of the homologous blood-cells by 

 the serum cannot be recognized. That the amboceptors present do 

 actually primarily protect the blood-cells of the corresponding species 

 is probable in itself, for according to our view, as mentioned elsewhere, 3 

 they represent free cell receptors. Besredka assumes that the reason 

 for the development of his supposed antiamboceptors is this: that 

 blood-cells, which are constantly dying in the organism, cause the 

 production of haemolysins. These would endanger life if the organ- 

 ism did not paralyze their action through the development of anti- 

 amboceptors. Such a regulating contrivance can surely not be very 

 common, since it was not observed by Ehrlich and Morgenroth in their 

 numerous experiments on isolysins, in which it would most readily 

 have been discovered. But if such a contrivance were a necessity, 

 it would have to be constant. This, however, is not at all the case 

 as we have alread} r established. 4 



The simplest and most natural assumption is that the antiambo- 

 ceptors are nothing else than products of cell disintegration, free 

 receptors which are capable of binding amboceptors and so exert a 

 deflecting influence. The assumption that these free receptors are 

 products of retrogressive metabolism is borne out by the fact estab- 



1 See page 88 et seq. 



2 P. Miiller, Centralblatt f. Bakt., Vol. 29, 1901. 



3 Morgenroth. (See page 241 et seq.) 



4 See pages 23 and 71 et seq. 



