208 



EDWIN J. COHX. 



higher concentrations of egg "extract." 1 In certain of the ex- 

 periments that are recorded the "fertilizing power" of the sperm 

 was increased in certain concentration of "egg water" but de- 

 creased in greater concentration. 



TABLE XV. 



THE EFFECT OF "Eco WATER" UPON THE LENGTH OF LIFE OF SPERMATOZOA. 



Experiment i?. 2 



Where the relative concentration of the "egg water' and 

 sperm is such that the activity of the sperm is decreased, the 

 length of life of the sperm, as measured by their ability subse- 

 quently to fertilize the ripe eggs of the same species in sea water, 

 is greater than is that of sperm that exhibit constant activity in 

 sea water for an equal length of time. This is to be expected 

 since the activity of spermatozoa is limited (Cohn, E. J., 1917). 

 Whereas the fertilizing power of sperm that have been in "egg 

 water" of various concentrations for but a few moments is often 



1 All of the properties of "egg water" and "egg extract" are not the same. 

 Sperm are, however, activated and agglutinated by both. 



- The actual strength of the "egg water" used in Experiment 17 is not known. 

 In all three suspensions, however, it gave at least a three minute agglutination. 



3 An egg extract was used in Experiment 13. 



4 An egg extract was used in Experiment 19. The strengths of the egg extracts 

 were as 1:5:25. The weakest gave a 7o-second agglutination. 



