32 ARTIFICIAL PARTHENOGENESIS AND FERTILIZATION 
are the independent variable, and that the oxidations are deter- 
mined or regulated by the hydrolytic processes. Our investi- 
gations do not contradict such a view. Since we are not able 
to measure the hydrolytic processes in the egg directly, we tried 
to solve our problem with the aid of the temperature coefficient. 
We determined the temperature coefficient for the velocity of 
segmentation in the egg of Arbacia by measuring the time 
which elapses from the moment of fertilization to the moment 
of the division of the egg into two cells for various temperatures. 
Then we measured the influence of the same variation of tem- 
perature upon the rate of oxidations in the cell. If the oxida- 
tions were the independent variable for the development of the 
egg the temperature coefficients for both processes should be 
identical or run parallel. This is, however, not the case. The 
experiments were made on the eggs of Arbacia at Woods Hole. 
The time which elapsed between fertilization and the first 
segmentation was as follows: 
TABLE II 
Time Required for Time Required for 
Temp. Deg. C.| First Segmentation Temp. Deg. C. First Segmentation 
Minutes Minutes 
die w eed neha Noxaless 498 20K acer soe 56 
Sipttceuassatenns 410 [ed Niet aie sashes esses 4 +43 
Ores cabarsnaedes 308 ZO) ORE ee 33 +363 
MO ierstaeyeteveceye 217 205 \tige creer 2 +313 
Le Sete otoustae 4 +143* Dg cars eee z+314 
5 ance ohiersiadeeecs 33+ 963 SOE cea 33 
MGS ercmeeelace 2 + 833 Siberia reheat OU 
a O91 ‘ 
df RNa 2>+68 32a teen No segmentation; 
18 | 68 35 eggs suffered 
1 
* Where the times are given in the form of a sum the eggs were put into the 
thermostat as many minutes after fertilization as the first figure indicates. 
The temperature coefficients for segmentation are the 
greater the lower the temperature. 
For the interval 7°-17° 
the coefficient is more than three times as large as for the interval 
17 .5°-27.5° (Table III). 
