392 



A. J. GOLDFARB. 



poor physiologic condition of the sperm as determined by tests 

 with fresh eggs. 



In every experiment, freshly liberated sperm raised the total 

 cleavage from o or nearly o to jo, 40, 50 and even 80 per cent, of the 

 eggs examined. There can be little doubt but that this means that 

 the apparent death of the eggs (when no cleavage occurred) IMS 

 really due to the precocious and rapid deterioration of the sperm, 

 with moderately little deterioration of the eggs. 



Hence to determine the exact physiologic condition of the eggs 

 at any stage in the ageing cycle, and to determine the real 

 longevity of the eggs, it is necessary to fertilize the eggs with 

 freshly liberated sperm at each testing, as F. R. Lillie, '14, had 

 done for a very 'different purpose. For example, the eggs of 4 

 females of experiment I, Table V., when }/% hour old, gave 95 



TABLE V. 



SHOWS REDUCTION IN CLEAVAGE WHEN AGEING EGGS ARE FERTILIZED BY FRESH 

 SPERM. SHOWS TRUE LONGEVITY OF EGGS. Toxopneustes. 



per cent, average cleavage; when 20 hours old, tested by fresh 

 sperm, 67 per cent.; when 23 hours old, 7 per cent.; when 24 

 hours old, 3 per cent.; when 25 hours old, i per cent.; when 46 

 hours old, ^2 P er cent.; when 48 hours old, o per cent. These 

 figures give a much more exact measure of the rate of deteriora- 

 tion of the eggs than when synchronously aged eggs and sperm 



