THE PROTECTIVE SUBSTANCES OF THE BLOOD. 381 



to illustrate the action of the two components by means of a crude 

 comparison, the action of gun and cartridge may be taken. The 

 complement in itself is harmless, like a cartridge, whicn only acquires 

 destructive power by being introduced into the gun. In like manner 

 only by the exclusive mediation of the amboceptor is the injurious 

 action of the complement called forth and transmitted to certain 

 particular elements. 



In opposition to this conception Bordet maintains the view that 

 complement and immune body do not combine as we believe, but 

 that the entrance of the immune body into the cell substance exerts 

 a specific injury to the latter, an injury which manifests itself by 

 the fact that now the cells succumb to the action of the simple pro- 

 tective substance present in blood serum, namely, Buchner's "alexin.' : 



In other words, by means of the immune substances the blood- 

 cells are made susceptible, "sensitized," to the action of the alexin. 

 In conformity with this Bordet terms our immune body or amboceptor 

 the "substance sensibilatrice" and our complement the alexin. 



Although this view is also shared by Buchner, there are many 

 reasons why I cannot accept it, especially in view of the observation 

 made by M. Neisser and F. Wechsberg concerning the peculiar phe- 

 nomenon of deflection of complement through an excess of immune 

 body. To begin it is absolutely impossible to picture to one's sell the 

 nature of this sensitization. If Bordet believes that the sensitizer acts 

 after the manner of a safety-key which, when introduced into a par- 

 ticular lock, makes the introduction of a second key possible, I must 

 say that I cannot understand this comparison. It can positively be 

 proven that the red blood-cell possesses no complementophile groups, 

 since neither in the normal state nor after death does it lay hold 

 of complement. The living blood-cell, as well as that killed by 

 heating, however, through the occupation with the immune body, 

 acquires the property to anchor complement. It surely is much more 

 natural to believe that the immune body itself, the amboceptor, is 

 the carrier of the group which binds the complement, than to assume 

 that new complementophile groups arise owing to the action of the 

 sensitizer. Finally, one can conceive of such a process in a living 

 cell, one therefore capable of alteration, but in the case of dead cells 

 which have been treated by heat or all sorts of chemicals, in the case 

 of stabilized albumin as one might say, this assumption cannot be 

 allowed. 



Bordet's assumption furthermore does not explain the fact that 



