590 JACQUES LOEB 



case they must remain in the alkaline solution for a consider- 

 ably longer time. 



4. The effect of the NH4OH can be inhibited or retarded by 

 the addition of a few drops of KCN to the solution. Since 

 our experiments indicate that only that part of the alkali can 

 act which diffuses into the egg, and since it was shown for- 

 merly by Wasteneys and the writer that in spite of its low degree 

 of dissociation NH4OH is about half as effective for the increase 

 in the rate of oxidations as KOH, the experiments suggest that 

 in the egg of the sea urchin the oxidations are not confined to 

 the external surface. 



