142 COLLECTED STUDIES IN IMMUNITY. 



related to the complement on the one hand (complement deflection !) 

 and to the corresponding bacterium on the other (specific absorption). 

 It is therefore an amboceptor in Ehrlich's sense, and not an anti- 

 alexin in that of Gruber. 



The results of my experiments may be summarized as follows: 



(1) By comparing two bactericidal immune sera both possessing 

 a strong agglutinating property, while, in certain combinations, only 

 one manifested the phenomenon of deflection of complement, the 

 objection was controverted that this deflection is due to the mechanical 

 action of agglutination. 



(2) It was possible to show in several different ways that the 

 deflection of complement is not caused by a constituent of normal 

 serum. 



(3) It was directly proven that the deflecting agent of the immune 

 serum is the specific amboceptor (immune body) produced by 

 immunization. 



From this it follows that the amboceptor merely plays the role 

 of a coupling element between bacteria and complement and that 

 the property of "sensitizing" (Bordet) or of "preparing" (Gruber) 

 cannot be ascribed to it. The latter assumptions seem to be irrecon- 

 cilable with the phenomenon of deflection of complements described 

 by Neisser and Wechsberg. 



