48 COLLECTED STUDIES IN IMMUNITY. 



Metchnikoff 1 has pursued this question as to the origin of the 

 antitoxins further. Since a positive conclusion did not seem pos- 

 sible to him by the use of the bacterial poisons, he employed a specific 

 cell poison, spermotoxin, which can be produced by treating guinea- 

 pigs with the testicle and epididymus of a rabbit. The use of this 

 poison has the advantage that the organs against which it is directed 

 can be removed from the animal without serious injury. As the 

 injection of this poison into the body of male rabbits is followed 

 by the production of an antibody, it was merely necessary to repeat 

 this procedure on castrated rabbits to decide the question whether 

 the antispermotoxin is produced only by the sexual cells or also 

 by other organs. 



The results showed that the sera of rabbits which had been injected 

 with this spermotoxin would protect rabbit spermatozoa against 

 the action of the spermotoxin no matter whether the rabbits from 

 whom these sera were derived had been castrated or not. 



According to Metchnikoff's view, this is opposed to the side- 

 chain theory, " since," as he says, " an antitoxin is produced with- 

 out the presence of corresponding receptors in the organism. " In 

 this, however, Metchnikoff starts with the assumption that the spermo- 

 toxin is absolutely specific and that it acts exclusively on sperma- 

 tozoa. He believes that the hsemolytic action which he has observed 

 in the spermatozoa immune serum may be explained by assuming 

 that with the injection of testis and epididymus red blood-cells were 

 introduced, and that these produced a haemolysin entirely independ- 

 ent of the spermotoxin. Further, he thinks that any relation of the 

 spermotoxin to other cells is excluded by the fact that in the serum 

 of guinea-pigs which have been treated with spermatozoa these 

 cells suffer no greater change than they do in normal guinea-pig 

 serum. 



Having made observations in the course of my investigations on 

 epithelial immunization, which contradict these assumptions of 

 Metchnikoff, I feel compelled to explain my views in order to clear 

 up the entire matter. 



As I have mentioned in a previous communication 2 the ciliated 

 epithelial immune serum is able, besides its specific action on ciliated 

 epithelium, to dissolve the red blood-cells of the same animal species. 



1 Annales de PInstitut Pasteur, 1900, No. 1. 



2 Munch, med. Wochenschrift, 1899, No. 38. 



