Artificial Parthenogenesis 117 



membrane formation could be prevented when the 

 eggs were deprived of oxygen or when the oxidations 

 were suppressed in the eggs by KCN. This suggested 

 a connection between the disintegration of the egg 

 after artificial membrane formation and the increase 

 in the rate of oxidations; and he found further that the 

 formation of acid is greater in the fertilized than in the 

 unfertiHzed egg. He, therefore, expressed the view 

 in 1906 that the essential feature (or possibly one of the 

 essential features) of the process of fertilization was 

 the increase of the rate of oxidations in the egg and 

 that this increase was caused by the membrane forma- 

 tion alone. ^ These conclusions have been since amply 

 confirmed by the measurements of O. Warburg as 

 well as those of Loeb and Wasteneys, both showing that 

 the entrance of the spermatozoon into the egg raises 

 the rate of oxidations from 400 to 600 per cent., and that 

 membrane formation alone brings about an increase 

 of similar magnitude. Loeb and Wasteneys found 

 that the hypertonic solution does not increase the rate 

 of oxidations in a fertilized egg. It does do so, how- 

 ever, in an unfertilized egg without membrane forma- 

 tion, but merely for the reason that in such an egg the 

 hypertonic solution brings about the cytolytic change in 

 the cortex of the egg underlying membrane formation. * 



* Loeb, J., Biochem. Ztschr., 1906, ii., 183. 



' Thus the treatment of an unfertilized egg without membrane with 

 a hypertonic solution combines two effects, first the general cytolytic 



