FERTILIZATION AND OXIDATION 35 
TABLE III 
Tomuereiare oo || vempersiurs Co- 
Piterralot efficient for 10°C. || intorvallot efficient for 10°C. 
Temperature |'Qormontationin || ‘Temperature fat the, Velocity, of 
the Egg of Arbacia | | the Egg of Arbacia 
7°-1 lig >, Soe We Nee SPAS Re eee 2.6 
8°-18" SYA ee 6.0 | GR 2Ge eee eae | 2.6 
9°19" SE ee 24.0 life esas oe 2.2 
MO 20 ges ote oe 3.9 PARE A A cieiaoe ire 
Demo trance Se B58 | 
A determination of the temperature coefficient of oxida- 
tions in the egg of Arbacia did not show such a variation. 
TABLE IV 
Temperature Co- Temperature Co- 
Interval of efficient for 10° Interval of efficient for 10° 
Temperature for the Velocity of Temperature for the Velocity of 
Oxidations Oxidations 
Del eiersterececcs « 2.18 op aee tie cameeies 2.24 
a Ge ee 2.16 DDS Aa Shore 2.00 
TW aS cere 2.00 20 SOR cote oie 1.96 
10290) ee Dela DOOD nv si. 1.40 
1eP ORS Saat 2.45 
The temperature coefficients of oxidations for a difference 
of 10° C. are practically identical throughout. For the interval 
7°-17° the coefficient is 2.0 and for 17°-27° it is also 2.0. This 
result points toward the probability that the rate of cell division 
is not directly determined by the rate of oxidations, although 
the possibility exists that besides the influence of temperature 
upon the velocity of chemical reactions an influence upon some 
physical property of the egg is superposed (e.g., viscosity) 
which makes itself felt only or chiefly at the lower temperatures 
and becomes the stronger the lower the temperature. 
6. The writer has shown that segmentation and develop- 
ment can go on only if the concentration of the HO ions in the 
surrounding solution reaches a certain height; this height is 
