THE PHYSIOLOGY OF FERTILIZATION 177 



in favor of Loeb's hypothesis that the fertilizing sub- 

 stance of the spermatozoon is a lysin. 



Herlant subsequently studied the same phenomenon 

 and pointed out that mere dilution of the sperm mix- 

 ture in the presence of eggs with pure sea-water would 

 result in some fertilizations, and that eggs that had 

 remained even seventy-five minutes in the mixture 

 could be fertilized with fresh species sperm if they 

 were repeatedly washed. He therefore doubted that 

 there was any profound alteration of either the male 

 or the female sexual elements, and postulated somewhat 

 doubtfully a physical alteration of the surface of the 

 egg in the presence of the sperm mixture. 



The two authors thus arrive at somewhat different 

 conclusions; the true solution may involve some com- 

 bination of these views. The present writer feels, for 

 reasons discussed later, that the serum analogy of 

 Godlewski is a true one in a very general sense, not 

 that the sperm carries a lysin, a conception that has no 

 longer any basis, but in the sense that reactions com- 

 parable to serum reactions probably are involved in 

 fertilization. If we were to suppose that the foreign 

 sperm prevents the agglutination of the species sperm 

 to the egg we would perhaps have a workable hy- 

 pothesis. 



In the cases of blood inhibition and sperm antago- 

 nism we have two forms of fertilization blocks that 

 suggest biochemical factors in which complex substances 

 play a role, and which therefore appear to belong to a 

 different category from deficiency of electrolytes or 

 acidity effect. 



