348 



CHARLES G. ROGERS AND KENNETH S. COLE. 



used was determined by centrifuging the suspension. After the 

 centrifuging, the eggs were deformed so that their volume repre- 

 sented almost all of the volume measured; thus it was possible 



30 



10- 



10 



lO 



20 



50 



30 



100 



ISO 



FIG. 3. Typical experimental curve. Heat production of Arbacia eggs. 

 Abscissae, time in minutes after fertilization. Ordinates, temperature differences 

 in micro-volts. ip.v = 0.001364 C. O 6 a observed values. - Of, observed 



values. O corrected curve. projection of corrected curve of 20 to 



50 minute period beyond the 50 minute position. 



to obtain an estimate of the total number of eggs used. This 

 method of counting was checked against a dilution method, 

 similar to that employed for counting blood corpuscles, and it 



