MASS PHYSIOLOGY OF SPERMATOZOA 



269 



gestion that the effect of dilution is related to a dilution of possible 

 foodstuffs. 



From such observations Cohn concludes that the basic factor con- 

 cerned in the greater functional longevity of the sperm composing 

 the more concentrated sperm suspensions is to be found in the de- 

 pressing action of the self-produced carbon dioxide upon the activity 

 of the relatively massed sperm. Similarly cyanides, dilute acids, 

 depleted oxygen, or anything that will paralyze the sperm without 

 killing them will prolong their ability to fertilize eggs. When dense 

 sperm suspensions, either fresh or after a period of some time, are 



TABLE XXIX 



Showing the Total Carbon-Dioxide Production 



OF Different Sperm Suspensions 



diluted with large quantities of normal sea-water, the H-ion con- 

 centration is markedly lowered, the activity of the sperm is much 

 increased, and the fertilizing power of the sperm suspension is like- 

 wise increased. But sperm so treated will lose their ability to fer- 

 tilize ripe eggs in sea-water long before spermatozoa that have been 

 relatively inactive in more acid sperm suspensions. Here we have 

 our fourth explanation of the unquestioned mass effect upon func- 

 tional longevity of spermatozoa, and the end is not yet. 



Cohn recognized that there is an H-ion aspect of these relations 

 not necessarily identified with the CO2 factor. Smith and Clowes 

 (1924) present direct evidence that such is the case, based on experi- 

 ments of CO^-free sea-water. They also show that here, too, there 

 is a definite extension of ability to fertilize eggs in higher H-ion 



