﻿IMMUNITY RESEARCH. 357 



due to bacterial particles causing precipitation. No essential solution 

 of bacterial substance, then, occurs in the animals, which fact agrees, 

 he thinks, with the one that typhoid bacilli after inoculation rapidly 

 acquire a resistance to bacteriolysis. However, with cholera, the case 

 is different, the exudate containing dissolved bacterial substance in 

 solution. 



"The conclusion is evident that it depends upon the course of an infection 

 whether an animal has in its exudate larger or smaller amounts of dissolved 

 bacterial substance." 



The smaller the amount of dissolved bacterial substance in an exudate, 

 as determined by complement deflection, the stronger is the aggressive 

 action of the exudate. 



These statements indicate a distinct recession from Bail's original 

 position, for on the one hand he acknowledges that artificial bacterial 

 extracts may contain aggressin and on the other, that aggressive exu- 

 dates may contain in solution other bacterial substances together with 

 aggressins. 



Bail also discusses at length the relation between complement deflec- 

 tion and precipitation, particularly with regard to its bearing upon our 

 understanding of aggressins. While artificial aggressins inhibit bac- 

 teriolysis, Bail notes that the third of a series of guinea pigs inoculated 

 in turn with cholera, furnishes a natural aggressin which contains com- 

 plement completing the action of anti-cholera serum. This complement 

 action of the aggressin exudate is stronger in the third than in the 

 second of a series of guinea pigs; and stronger in the second than in 

 the first. This change is so regular that when it is absent it is safe to 

 attribute it to an overdose of bacteria in setting the test. 



In serial inoculations aggressivity increases until the danger arises 

 that the series will cease from some cause not clearly understood. As 

 the aggressivity increases, there is a decrease in the power of the exudate 

 to block haemolysis. Bail brings this forward in rebuttal of Citron's 

 argument that the power to block haemolysis furnishes an index of the 

 aggressivity of the exudate. He discusses the phenomena of precipita- 

 tion, complement deflection and multiplicity of complements. He 

 agrees completely with Moreschi that deflection is not a function of the 

 union of amboceptors with specific substances, but is due to gross or 

 microscopic precipitation. 



He states that he disregards the plurality of complement idea, which 

 he thinks was overthrown by the discovery of complement deflection, 

 and he agrees with Bordet in looking upon complement as a "single 

 fermentative, complementative activity" of the body juices. However, 

 he is not consistent in this position, for he finds that in some of his 

 aggressin experiments the heart's blood of the animal contains hemolytic 



