ARTIFICIAL PARTHENOGENESIS AND OXIDATIONS 115 
superficial cytolysis or a cytolysis of the cortical layer of the 
egg. It is obviously this cytolysis and no subsequent morpho- 
logical change in the egg which causes the increase in the rate 
of oxidation. We can cause complete cytolysis of the eggs of 
the sea-urchin by adding a trace of saponin to the sea-water. 
Wasteneys and I measured the rate of oxidations in a lot of 
unfertilized eggs in sea-water and found that they consumed 
0.15 mg. O, per hour at 15°C. Then the eggs were cytolyzed 
with saponin and the amount of oxygen consumed in one hour 
at 15° C. was measured again. It was 1.07 mg. The cytolysis 
of the eggs increased the rate of oxidation 700 per cent, as much 
as, or possibly a trifle more than, fertilization. In a similar 
experiment in which dilute sea-water was used for cytolysis and 
in which not all the eggs cytolyzed, the rate of oxidation was 
increased 2.74 times after the cytolysis. The cytolyzed eggs 
are no longer able to undergo any development or structural 
change. It is therefore obvious that the increase in the rate 
of oxidation after membrane formation as well as after fertiliza- 
tion is due to the mere cytolysis. How the cytolysis can bring 
about such a result is unknown. 
2. The greatest interest was attached to the question as to 
how the hypertonic solution affected the oxidations in the eggs 
after membrane formation. It was found that the eggs in 
which the artificial membrane formation had been induced 
with butyric acid consumed oxygen in the hypertonic solution 
at the same rate as in normal sea-water. 
Some of the eggs of the last-mentioned experiments were 
also used to compare the rate of oxidation in such eggs in normal 
sea-water and in hypertonic sea-water (50 c.c. sea-water+8 ¢.c. 
24 m NaC!+KCl+CaCl,). 
Oxygen consumption of unfertilized eggs after artificial 
membrane formation 
imenermal sea-water. 2... 5. .% os aise 0.85 mg. 
In hypertonic sea-water...............0.88 mg. 
