52 COLLECTED STUDIES IN IMMUNITY. 



ceptors for the immune body of the spermatozoa immune serum 

 are present not only in the organs of generation but also in other 

 cells of the rabbit. When, in addition, we come to consider the 

 results of these last experiments, we find that the demonstration 

 of Metchnikoff (that even in castrated animals, in response to treat- 

 ment with spermotoxin, a body is developed which prevents the 

 action of the spermotoxin) loses all value as proof for the origin of 

 a specific antispermotoxin. 



The active spermotoxin employed by Metchnikoff is of course not 

 a simple poison; it consists, just like a haemolysin, of the specific 

 immune body obtained by immunization and the complement present 

 in all guinea-pig serum. Now it has been shown independently by 

 Ehrlich 1 and Bordet 2 that when the complement is injected into 

 foreign species it excites the production of an anticomplement which 

 inhibits the action of an active immune body by taking away the 

 complement, and that it does this without possessing any specific 

 affinity to this immune body. 



It is therefore possible that the action of the antispermotoxin 

 obtained by Metchnikoff is to be explained thus: The injected 

 guinea-pig serum by virtue of the complement ( Bordet 's alexin) 

 which it contains, causes the production of an anticomplement 

 serum which then renders the complement of the spermotoxin (de- 

 rived from guinea-pigs) innocuous. With this idea, Bordet has ex- 

 amined an antihaemolysin, which is analogous to the antispermo- 

 toxin, and has found that the action of the anticomplement is much 

 more pronounced than that of the anti-immune body. The forma- 

 tion of an anticomplement does not, of course, according to the side- 

 chain theory, presuppose the presence of spermatozoa; for accord- 

 ing to my experiments the complement may possess affinities for the 

 most varied cells of the organism. 



Ehrlich's theory, that the antitoxins are produced by those 

 organs which possess chemical relations to the toxins, is therefore 

 in no way affected by the observations of Metchnikoff. 



B. Milk Immune Serum. 



After it had been found that it is possible to produce a specific 

 immune serum by injecting guinea-pigs with ciliated epithelium from 



1 Croonian lecture, Royal Society, London, March 1900. 

 8 Annal. de ITnstitut Pasteur, May 1900. 



