854 



GENERAL METABOLISM 



[PT. Ill 



had, of course, an injurious effect, and the maximum was obtained 

 when 1-75 CO. of JV/io NaOH were added to 100 c.c. of sea water. 

 He attempted to raise the eggs of Strongylocentrotus from fertiHsation 

 in neutral Ringer's solution without success, but found that with the 

 addition of a little potassium hydroxide or sodium bicarbonate it was 

 possible to do so. He concluded that a neutral or faintly alkaUne 

 solution was necessary for normal development, and subsequent 

 experiments by Herbst and by Peter only confirmed this view. Moore, 



Roaf & Whitley, investigating Echinus eggs, found exactly the same 

 relationships — the smallest amount of acid inhibited growth and 

 cleavage, but alkali had first a stimulatory and then an inhibitory 

 effect. In a later paper, Whitley could not find any evidence of the 

 favourable effect of mildly alkaHne hydrogen ion concentrations in 

 the case of the eggs of the plaice, Pleuronectes platessa, but reported 

 that a change of />H towards the acid side was much more fatal than 

 one towards the alkaline side. Loeb's work with Arbacia eggs was 

 repeated by Glaser, who also observed the stimulatory effect of small 

 amounts of alkah, but emphasised that this is hmited to the post- 

 blastula stages, for the cleavage-rate at the beginning may even be 



