268 



ANIMAL AGGREGATIONS 



An inspection of this figure will show that the spermatozoa lived 

 longest in the most concentrated sperm suspensions. Further, Cohn 

 undertook to study the total carbon-dioxide production of sperm 

 suspensions at different dilutions, with the results shown in Table 

 XXIX. These results show that in the less concentrated suspen- 



8 (0 12 14 



T/M£ /Af HOURS 



Fig. 27. — Showing the length of life of the different concentrations of sperm sus- 

 pensions shown in the preceding figure as measured by the percentage of eggs fertilized 

 (ordinates) after given lapses of time (abscissas). (From Cohn 1918.) The legend for 

 concentrations is the same as in the preceding figure. 



sions which more nearly approximate normal conditions, spermato- 

 zoa that live for longer periods of time produce no more carbon 

 dioxide than do those living for only 4 hours. Roughly speaking, 

 the total production of carbon dioxide approaches a constant ; hence 

 the total available energy of spermatozoa must be a constant, and 

 the rate at which this energy is expended is a function of the activity 

 and an inverse function of the length of life of the spermatozoa. 

 These results argue in favor of Gemmil's assumption that length of 

 life is associated with the amount of activity, and against his sug- 



