X. THE DEFLECTION OF COMPLEMENTS IN BACTERI- 

 CIDAL TEST-TUBE EXPERIMENTS. 1 



By Dr. A. LIPSTEIN, Assistant in the Bacteriological Division. 



IN a study published in 190 1, 2 Neisser and Wechsberg described 

 a peculiar phenomenon occurring hi bactericidal test-tube experi- 

 ments. This phenomenon consisted in the fact that the bacteria 

 were not killed despite the presence of the appropriate bacterial 

 amboceptor (immune body) and complements when a compara- 

 tively large excess of amboceptor was present. This fact, for which 

 all other explanations failed, was explained by the authors on the 

 basis of Ehrlich and Morgenroth's views. They assumed that, with 

 certain conditions of affinity, an excess of amboceptors exerts a 

 deflecting and at the same time a diluting action on the complement; 

 as a result the complement does not combine with the amboceptors 

 anchored to the bacteria, but with the superfluous free amboceptors, 

 while the amboceptors which are anchored to the cells remain without 

 any complement. Now since only those complements exert a bac- 

 tericidal action which are anchored to the bacteria by means of the 

 amboceptors, it follows that in this case there will be no bactericidal 

 action. Naturally this phenomenon of deflection of complement 

 does not occur with every combination of amboceptor and comple- 

 ment, but only when certain conditions of affinity are present. Later 

 I shall be able to show how the same amboceptor in excess exerts a 

 deflecting action on one complement while it fails to do so on two 

 other complements. Because of the theoretical importance of this 

 phenomenon and its explanation, a continuation of the experiments 

 of Neisser and Wechsberg, taking special cognizance of the objections 

 since made, seemed desirable. 



1 Reprinted from Centralblatt fur Bact., Vol. XXXI, No. 10, 1902. 



2 See page 120 of this volume; also Wechsberg, Zeitschr. f. Hygiene, Vol. 39, 

 1902. 



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