OF EXPERIMENTAL WORK 217 



Keltch, Neubeck, and Clowes, 1941 ; Hutchens, Kopac, and Krahl, 1942). Oxygen 

 consumption of cell-free system of unfertilized eggs about three times that of same 

 weight of intact unfertilized eggs and about same as that of equal weight of fertilized 

 eggs (Keltch, Strittmatter, Walters, and Clowes, 1950). Slightly different figures 

 given by Crane and Keltch (1949). Stimulation by dinitrocresol and phosphate; 

 also methods (Crane and Keltch, 1949). Oxidative phosphorylation (Keltch, et al., 

 1950; Clowes, Keltch, et al., 1950; Strittmatter, et al., 1950; Clowes, et al., 1951 a, b; 

 Keltch, et al., 195 1). 



VII. Carbon Dioxide Production 



Nearly equivalent increase on increase of O., consumption (Clowes and Krahl, 

 1936 a). See Ballentine (1940 b, c). Carbon dioxide production occurs in rhythms in 

 segmenting eggs, greatest at time of active division (Lyon, igo4a, b). 



VIII. Respiratory Quotient 



RQ_, of fertilized eggs 0.78 (Amberson, 1928); 0.71 (Root, 1930). Of eggs one to 

 25 hours after fertilization 0.86 (Hutchens, Keltch, Krahl, and Clowes, 1942; Krahl, 

 1950)- 



IX. Temperature Coefficient, Q,io (Table 19) 



Fertilized eggs, about 2 (3°-27 °C.) (Loeb and Wasteneys, 1911a; Loeb, 1913a, 



P- 33)- 



Unfertilized eggs, 4.1 ; fertilized eggs 1.8; cytolysed eggs 1.9 (i3°-30 °C.). Increase 

 of O2 consumption on fertilization depends on temperature, 8 times as great at 

 1 1 °C., and twice as great at 29.9 °C. ; there should be no increase at 32 °C. (Ruben- 

 stein and Gerard, 1934). 



TABLE 19 



TEMPERATURE COEFFICIENTS, q,o FOR VELOCITY OF OXIDATIONS 

 AND OF FIRST CLEAVAGE OF ARBACIA PUNCTULATA 



Loeb and Wasteneys, 1911a; Loeb, 1913a, p. 33; Loeb and 

 Chamberlain, 19 15 



