366 STUDIES IN IMMUNITY 



of molecular adhesion that is the essential cause of the agglutination 

 of bacteria? Is it not a change in molecular adhesion that makes 

 bacteria treated by an agglutinin flock out when sodium chloride 

 is added, although normal bacteria do not? 



From this viewpoint alexin fixation assumes a more real and 

 general interest than was at first apparent. In endeavoring to 

 understand the reactions that take place in the body by comparison 

 with simpler and better-known facts, is it necessary to look for 

 analogies in pure chemistry alone, as do Ehrlich and Morgenroth? 

 Such phenomena, as we know, follow laws of definite proportions, 

 and give rise to compounds of unvarying constitutions described 

 by a formula. But may we not also cite analogies among the 

 phenomena of molecular adhesion, flocculation, coagulation, emul- 

 sion, dyeing, stickiness and the like? 



When we try to prove the principal proposition of Ehrlich and 

 Morgenroth experimentally, namely, that the sensitizer can com- 

 bine with the alexin without the presence of corpuscles, negative 

 results are obtained ; the alexin remains quite free, as was demon- 

 strated in earlier experiments, to which the reader is referred.* 



In endeavoring to prove their assertion Ehrlich and Sachsf have 

 laid much stress on the supposed complement deviation evidenced 

 by the well-known experiments of Neisser and Wechsberg on the 

 antibacteriolytic effect of an excess of sensitizer in presence of a 

 relatively small dose of alexin. 



This complement deviation is due, according to the authors in 

 question, to the fact that the excess of sensitizer which is refused by 

 the saturated bacteria remains free in the fluid and takes up on 

 its own account part of the alexin and so prevents it from destroy- 

 ing bacteria; this supposition was never proved experimentally. 

 Several authors have recently questioned Neisser and Wechsberg's 

 explanation of their phenomenon and have offered new explanations 

 which have no part with the thesis defended by the Ehrlich school. 

 (Gay,J Moreschi, Buxton.||) 



* Bordet, The cytolytic sera, etc., p. 228. 



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

 Sons, p. 217. 



t Gay, see p. 357. 



$ Moreschi, Berliner klinische Wochcnschrift, 1906, p. 100. 



II Buxton, Journal Med. Research, XII, 1 ( J05, 431. 



