382 OTTO GLASER. 



as the essential point in the initiation of development, the relief 

 of antagonistic conditions. When I found that the egg-secretion 

 in certain concentrations actually retards development, I thought 

 I had located the antagonists, and, without knowledge of the 

 earlier and similar suggestion by R. S. Lillie ('09), postulated 

 that initiatory agents are effective "because through increased 

 permeability of the plasma film the egg is enabled to loose sub- 

 stances antagonistic to oxidation" ('i3 3 , p. 450). 



It would of course have been more conservative to say "an- 

 tagonistic to development," for the retardation brought about by 

 the secretions and extracts may be the outcome of interferences 

 with other conditions and processes, no less essential for normal 

 development, than the oxidations. Indeed Loeb and Wasteneys 

 ('n) have demonstrated the independence of the temperature 

 coefficients of oxidation and cleavage, so that retardation of the 

 latter is not synonymous with a depression of the former. Again 

 the secretion, in the concentrations in which it was employed, 

 brings about abnormal permeability relations which might 

 account for the retarded development, and the possibility that 

 the substances involved have one effect in the concentrations in 

 which they occur in the unfertilized egg, but different effects in 

 the higher concentrations of the experiments, must not be over- 

 looked for good analogies are to be found in the effects of different 

 concentrations of ether (R. S. Lillie, 'i2 2 , p. 373). While it 

 may yet be true that the delaying effect of the secretion is actually 

 the outcome of a depression in the rate of oxidation, proof of 

 this must be sought in further experiments. 



However, even if further experimentation should succeed in 

 tracing the retarded development to a decrease in the oxidation 

 rate brought on by the presence of the egg-exudate, a difficulty 

 would still remain, for the surface film of the unfertilized ovum 

 is permeable for the secretion, and so by constant elimination 

 an accumulation of the suspected antagonist to the inhibition 

 point would be automatically prevented. This is the argument 

 applied by Loeb in contraversion of R. S. Lillie's idea that CO 2 

 might be the antagonist, for inasmuch as CO 2 "is a good agency for 

 calling forth membrane formation" and as only substances capa- 

 ble of diffusing into the egg can have this effect, the egg surface 



