STUDIES IN THE PHYSIOLOGY OF SPERMATOZOA. 1 95 



Spermatozoa that have been in alkaline sea water have a 

 greater "fertilizing power" than spermatozoa that have been in 

 sea water at the hydrogen ion concentration of the ocean. This 

 becomes apparent only at dilutions such that the spermatozoa 

 that have been in the less alkaline sea water do not fertilize all 

 of the eggs. If all of the eggs are not fertilized, it must be either 

 (a) because there are not enough spermatozoa or (&) because the 

 spermatozoa are not sufficiently potent. Since the same, con- 

 centration of sperm is able to fertilize completely at another hy- 

 drogen ion concentration, the first alternative does not explain 

 the results in these experiments (Experiment 20, 21, 226, 227-!.). 



If the "fertilizing power" of active spermatozoa were exactly 

 proportional to the energy expended, the areas beneath the 

 curves in the diagram would be exactly equal, since the total 

 available energy of spermatozoa is practically constant (p. 183). 

 If the relation is not as simple as this, it is at all events perfectly 

 definite and definable, and strongly suggestive of a simple func- 

 tional relation, at least during the first few minutes of the life 

 of the sperm. 1 



THE EFFECT OF THE SPERM CONCENTRATION UPON THE "FER- 

 TILIZING POWER" OF SPERMATOZOA. 



"In his epoch-making 'Experiences pour servir a 1'histoire de 

 la generation des animaux et des plantes' published in 1785 the 

 Abbe Spallanzani describes among his numerous experiments on 

 fertilization and artificial parthenogenesis some determinations 

 concerning the minimal quantity of sperm necessary to fertilize 

 the eggs of the frog" (Lillie, F. R., 1915, p. 229). "In 1824 

 Prevost et Dumas confirmed these" results (Lillie, F. R., 1915, 

 p. 229). More recently in the "Analysis of Variations in the 

 Fertilizing Power of Sperm Suspensions of Arbacia" (Lillie, F. R., 

 1915, p. 229) that has already been quoted, F. R. Lillie demon- 

 strated that at "a dilution of 1/10,000 per cent.," where "one 

 can rarely find a single spermatozoon in the jelly of the fertilized 



1 Thereafter it is difficult to conceive of the physiological condition of the 

 spermatozoon as suffering no alteration. A change in the physiological condition 

 must in turn affect the "fertilizing power." Strong evidence for the view that 

 the ageing of Echinid sperm affects its physiological condition has previously 

 been presented by Dungay (1913) and Vernon (1899). 



