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 2| 

 hours into hypertonic sea-water (50 c.c. sea-water-f8 c.c. 2| 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. 



> Loeb, Jour. Exper. Zool, XV, 201, 1913. 



