l.o 



HEAT PRODUCTION BY EGGS. 



349 



was found that the agreement was very close, and that the eggs 

 showed less variation than did the number of eggs in the fractions 

 counted. 



The course of a typical run is shown in Fig. 3. In it the 

 average diameter of the eggs was 74 microns, and the total 



-L 



_L 



50 



100 



150 



FIG. 4. Rate of heat production, Arbacia eggs. Abscissae, time in minutes 

 after fertilization. Ordinates, rate of heat production in calories per hour per 

 million eggs. 



volume was 0.82 cc. The total number of eggs was, therefore, 

 about 3.9 millions. About 96 per cent, of these eggs were 

 fertilized and of those fertilized about 85 per cent, were in the 

 eight cell stage, and the rest in a late four cell stage and going 

 into the eight cell stage so rapidly that an accurate percentage 

 could not be obtained, when the experiment was concluded. 

 In Fig. 3 every fifth reading is plotted. The corrected curve 

 was obtained by taking approximate values of the integrals of 

 equation (3) for five minutes intervals. The greatest variation 

 in the different runs is in the behavior during the first twenty 

 minutes after fertilization. This is probably due to the fact 

 that the amount of sperm could not be made proportional to the 

 number of eggs, and that the heat production of the sperm is not 

 negligible during this period, as will be shown later. In this 



