Mechanism of immunity against micro-organisms 199 



by the phagocytes, debris of indeterminate form may, for long, be 

 found in the cells, but I have never been able to demonstrate any 

 solid excreta from them. We must suppose, then, that the undigested 

 portions are not thrown out from the phagocytes. 



When describing the solution of red blood corpuscles by normal 

 serums, we have mentioned Ehrlich and Morgenroth's view that 

 the cytases are incapable of fixing themselves to these cells with- [210] 

 out the help of fixatives. They cite in support of their opinion 

 several examples of fixatives (intermediary substances or " Zwischen- 

 kbrper") discovered by them in the serums of various species of 

 mammals. Is this so with microcytase in respect to micro-organisms ? 

 If this soluble ferment is incapable alone of fixing itself upon the 

 bodies of these parasites, the help of fixatives would be indispensable 

 to it. The bactericidal property of the microcytase, then, would 

 depend on the existence of another body (fixative) which, perhaps, 

 might not owe its origin to phagocytes. The problem, then, has a 

 wide general range. 



In one of his memoirs, Bordet 1 had already raised the question of 

 the existence of this sensibilising (or fixative) property in normal 

 serums. By mixing two normal serums coming from different species, 

 he was sometimes able to demonstrate the existence of such fixatives. 

 Thus the cholera vibrios, which do not undergo granular transforma- 

 tion in either the normal serum of the horse (which is capable only 

 of arresting their movements and agglutinating them into a mass) 

 or in that of the normal guinea-pig, readily become transformed into 

 granules when placed in contact with a mixture of the two serums. 

 Bordet, however, refrains from any hasty generalisation on this 

 observation and proposes to make fresh researches on this subject 

 Independently, Moxter 2 has attempted to demonstrate the presence 

 of fixative in the normal serum of the guinea-pig. When deprived 

 of cytases by heat, this serum is incapable of transforming the cholera 

 vibrios into granules ; but when fluid from the peritoneal exudation 

 of the same guinea-pig is added, the transformation takes place 

 very rapidly. Nevertheless, as this exudation was already, by itself, 

 capable of producing Pfeiffer's phenomenon, Moxter's conclusions on 

 the presence of the fixative in the normal guinea-pig's serum cannot 

 be accepted without a fuller analysis of the facts, and this deman 

 fresh researches. 



1 Ann. de FInst. Pasteur, Paris, 1899, t. xin, p. 295. 



2 CentralbLf. Bakteriol u. Parasitenk., Jena, 1899, I w Abt, Bd. xxvi, b. 



