438 STUDIES IN IMMUNITY. 



given substance, when salts are added, by the same method. 

 This adhesive power, which the hemolysin in eel serum has only 

 when electrolyes are present, would seem to exist normally in other 

 substances, either for other suspended elements or for other particles 

 of their own suspension. 



This faculty of adhesion which is spontaneous with certain mate- 

 rials, and is brought about only when electrolytes are present in 

 other materials, is combated by the citrate, which substitutes one 

 adhesion for the other adhesions which these substances may show. 

 The action of the citrate, its mechanism and the opposing effect of 

 electrolytes are precisely the same whether we study them in distinct 

 adsorption phenomena, such as the adsorption of one substance in 

 colloidal solution (gum arabic), or in suspension (corpuscles) with 

 an insoluble substance (barium sulphate), or when we study the 

 hemolytic phenomena produced by the biological agents that have 

 been studied by bacteriologists. 



*** 



It should be recalled in this connection that Bordet has long 

 maintained that the neutralization of a toxin by an antitoxin is 

 comparable to the phenomena of dyeing rather than to the ordinary 

 chemical reactions expressed by equations. We cannot mention 

 all the facts that serve to support this theory, in this place, but we 

 may recall that certain experiments led Bordet to postulate that 

 the dose of alexin, fixed by a given quantity of corpuscles, would 

 vary according to the initial mass of alexin that was present. 

 Certain other researches also led him to the conclusion that a given 

 dose of anti-alexin will neutralize variable amounts of alexin in 

 accordance with the manner in which the two substances are mixed. 

 We meet with the same fact in considering the neutralization of 

 certain toxins by their antitoxins ; this fact is generally described as 

 Danysz' phenomenon. 



It was particularly on the basis of the facts concerned in the 

 reactions of alexin with corpuscles on the one hand and with anti- 

 alexin on the other, that Bordet formed his theory of the neutral- 

 ization of toxins by antitoxins. It seems not without interest to 

 compare this writer's conceptions with the conclusions which we 

 have arrived at in this work, in so far as concerns the mode of 



