Resorption of the formed elements 101 



that the blood serum and the peritoneal fluid of animals that have 

 been injected with the spermatic fluid of bull, rabbit, or man, be- 

 come spermotoxic, that is to say, they render the corresponding 

 spermatozoa motionless and kill them. These fluids, however, never 

 acquire the power of dissolving, even partially, these elements. 

 The disappearance and final solution of the spermatozoa is only 

 effected within phagocytes, and almost exclusively in the macro- 

 phages. 



Moxter 1 has demonstrated that the spermotoxin which appears in 

 the serum of prepared animals consists of two substances, corre- 

 sponding to those present in the haemolytic serums. These are the 

 macrocytase (alexine, complement) and the fixative (intermediary or 

 sensibilising substance). For him they are identical with those which 

 dissolve the red corpuscles. Without dwelling on the subject we 

 may say that the macrocytase which dissolves the red corpuscles 

 and that which arrests the motion of the spermatozoa are really 

 identical in the same species of animal, as is accepted and developed [108] 

 by Bordet. On the other hand, it is impossible to accept Moxter 's 

 theory of the identity of the two fixatives. They must be regarded 

 as different ; this we have attempted to prove in one of our memoirs 2 

 and is in accordance with the law of the specificity of fixatives in 

 general. 



The question which interests us more especially at this moment 

 is where are these two constituent substances of the spermotoxin 

 to be found and how do they behave in the living organism ? This 

 question has been very thoroughly studied by Metalnikoff 3 in my 

 laboratory. His experiments have been closely followed by me, and 

 in presenting their principal results I can bear witness to their 

 correctness. 



The spermotoxin obtained by Metalnikoff is distinguished from 

 the haemotoxins we have discussed up to the present in that they 

 develop, not as a result of the injection of cell elements from a diffe- 

 rent species, but as a result of the introduction into the organism of 

 spermatozoa from the same species, the guinea-pig. We have here, 

 then, to deal with what has been termed autospermotoxin. 



The serum of the normal guinea-pig acts but feebly on the sper- 

 matozoa of this species, which, under its influence, remain motile for 



1 Deutsche med. Wchnschr., Leipzig, 1900, S. 61. 



2 Ann. de I'Inst. Pasteur, Paris, 1900, t. xiv, p. 369. 



3 Ibid., p. 577. 



