RELATIONS OF SENSITIZERS TO ALEXIN. 367 



In their studies on snake venoms Kyes and Sachs * found an 

 apparent confirmation of this explanation of complement devia- 

 tion, but Hideyo Noguchi f later showed that their phenomena were 

 to be explained quite differently. 



There is, then, no valid reason for conceiving, as Ehrlich and 

 Morgenroth do, that, when an alexin is not able to destroy a given 

 corpuscle sensitized with a certain sensitizer, the failure is due to 

 the inability of the alexin to combine with the sensitizer in question. 

 The fact that an alexin does or does not destroy in a given case is 

 not dependent on its adaptability or non-adaptability to a sup- 

 positious complementophilic group of the sensitizer employed. 

 The designations "passende" or "nicht passende Komplemente" 

 do not indicate any real condition. 



And, indeed, with what alexin should a sensitizer in horse serum 

 most readily unite logically? It is evident that it should combine 

 with an alexin from the same animal species — the horse. But as a 

 matter of fact, although horse serum contains a sensitizer that 

 hemolyzes guinea-pig corpuscles in conjunction with guinea-pig 

 alexin, no such result occurs with horse alexin. 



Are we to suppose that this sensitizer unites with the first alexin 

 better than with the second? Or is it not more reasonable to con- 

 clude that both alexins are absorbed by the sensitized corpuscles, 

 but that the horse alexin is simply less toxic and less liable to cause 

 hemolysis? $ 



As another example we may note that normal rabbit serum 

 contains a sensitizer for goat corpuscles. This sensitizer, however, 

 is much more effective with guinea-pig alexin (which alone does 

 not hemolyze, as the serum of the guinea-pig contains no sensitizer) 

 than with rabbit alexin. § 



* Kyes and Sachs, Studies on Immunity, Ehrlich-Bolduan, John Wiley & 

 Sons, p. 443. 



f Noguchi, Jour, of Exp. Medicine, VII, 1905. 



} In the same way we shall later show that although horse alexin is well 

 absorbed by sensitized ox corpuscles it fails to hemolyze them. Analogous 

 instances have already been noted by Muir (Proceedings of the Royal Society, 

 Vol. 74, 1904, 305) and by Gay (this volume, p. 336). 



$ Experiment. One cubic centimeter of a 10 per cent suspension of goat 

 blood in salt solution is placed in each of four tubes. To tube "a" is added 0.4 

 of a cubic centimeter of fresh rabbit serum, to tube " b" 0.2 of a cubic centimeter 

 of fresh guinea-pig serum, to tube " c " 0.2 of a cubic centimeter of rabbit serum 



