ARTIFICIAL PARTHENOGENESIS AND OXIDATIONS 119 
about three hours, or the addition of some KCN to the sea- 
water for the same period of time after the artificial membrane 
formation, can act as a substitute for the 40 to 60 minutes of 
treatment of the eggs with the hypertonic solution. It is con- 
ceivable that the hydrolytic processes which continue to go on in 
the egg after the retardation of oxidations lead to the formation 
of a substance (or to a condition) which at the normal rate of 
oxidation could not be formed (or arise), or if formed would be 
rapidly destroyed, and which acts similarly as the substance 
formed in a much shorter time through the oxidations if the 
amount of water in the egg is diminished. 
5. The idea that the curative or corrective effect of the 
hypertonic solution consists in the formation in the egg of a 
substance which remedies the danger of disintegration follow- 
ing artificial membrane formation is supported by another fact. 
We have already stated that the treatment of the egg with the 
hypertonic solution may precede the artificial membrane forma- 
tion. -But the writer succeeded in showing last winter that if 
the eggs are once treated with the hypertonic solution they are 
permanently immune against the disintegration which follows 
artificial membrane formation.! 
Unfertilized eggs of S. purpuratus were put for 2 and 24 
hours into hypertonic sea-water (50 c.c. sea-water+8 c.c. 24 m 
Ringer). Some of them were treated about ten minutes later 
with butyric acid, and the majority of them developed into 
larvae. Others were treated with butyric acid 24 hours, 
48, and 72 hours later. Those treated 24 hours later with 
butyric acid developed also and about as well as those treated 
immediately. After 48 hours a great many eggs were dead, 
but those that were still alive or had not suffered too much still 
developed into larvae when treated with butyric acid. After 
three days almost all the eggs were dead, but those that were 
still intact segmented and developed into swimming larvae after 
the butyric-acid treatment. 
1 Loeb, Jour. Exper. Zool., XV, 201, 1913. 
