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 O. 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.! 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’ 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 
role 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. 
