114 ARTIFICIAL PARTHENOGENESIS AND FERTILIZATION 



concluded that the artificial membrane formation increases the 

 rate of oxidations in the egg. 



The correctness of this surmise was proven by 0. Warburg, 

 who compared the effect of the artificial membrane formation 

 upon the oxidations in the egg with that of fertilization by 

 sperm. The ratio was 10.5 for eggs fertilized by sperm and 

 9.0 for eggs after artificial membrane formation. 1 Hence the 

 effect of the artificial membrane formation upon the rate of 

 oxidations was nearly the same as that of fertilization by sperm. 

 Warburg's experiments were performed on the egg of S. lividus 

 at Naples. Wasteneys and I repeated the experiments 2 on 

 the eggs of S. purpuratus at Pacific Grove. 



In three experiments on S. purpuratus the ratio of oxygen 

 consumption between unfertilized and fertilized eggs was 

 1/6.87, 1/5.45, and 1/5.60. 



A comparison of the oxygen consumption of unfertilized 

 eggs before and after membrane formation by butyric acid gave 

 in one experiment a ratio of 1/4.72; in a second experiment a 

 ratio of 1/4.28. Since this figure was a little lower than the 

 ratio found between unfertilized and fertilized eggs, part of the 

 eggs of the same females were utilized to determine the rate of 

 oxidation in the unfertilized and fertilized egg. It was found 

 to be 1/4. 55. We may therefore state that the artificial mem- 

 brane formation raises the rate of oxidations to approximately 

 the same height as the entrance of a spermatozoon. This 

 confirms the conclusion the writer had drawn concerning the 

 r61e of the artificial membrane formation, namely, that it is the 

 essential feature in the activation of the egg; and second, that 

 the activation consists in an increase in the rate of oxidations. 

 The question then arises, In which way can the artificial mem- 

 brane formation increase the rate of oxidation? We may 

 anticipate here what will be proved extensively in subsequent 

 chapters, that the membrane formation may be considered as a 



1 Warburg, Zeitschr. f. physiol. Chem., LXVI, 305, 1910. 



2 Loeb and Wasteneys, Jour. Biol. Chem., XIV, 469, 1913. 



