196 



EDWIN J. COHN. 



TABLE IX. 



THE EFFECT OF THE HYDROGEN ION CONCENTRATION OF THE SUSPENSION UPON 

 THE FERTILIZING POWER AND UPON THE LENGTH OF LIFE OF 



SPERMATOZOA. 



Experiment 228. 



Experiment 215. 



eggs" (Lillie, F. R., 1915, p. 234) about 95 per cent, of the eggs 

 were fertilized if the time, which "is an extremely important 

 factor with reference to fertilizing power" (Lillie, F. R., 1915, 

 p. 234) during which the sperm were in sea water, was short. 

 For: "If the sperm suspensions lose their fertilizing power with 

 time, it must be that the significance of time in this respect 

 varies inversely to concentration" (Lillie, F. R., 1915, p. 239). 



I believe that Lillie's results have conclusively demonstrated 

 that one sperm is quite sufficient to fertilize an egg if it has not 

 already expended a large part of its available energy. There- 

 after the statement that "the initiation of development by a 

 single spermatozoon ... is impossible because a single sperm 



