ENVIRONMENT AND REGENERATION 463 



weaker bases were better than those of NaOH, Loeb concluded 

 that the results were not due to the free OH ions, but to the 

 ability of the base to neutralize the acids produced by the 

 tubularian. 



Loeb and Wasteneys ('13 a and b) have shown that bases 

 increase the rate of oxygen consumption both in the fertilized 

 and unfertilized eggs of Strongylocentrotus purpuratus, but that 

 in fertilized eggs this increase in oxygen consumption is accom- 

 plished only by concentrations which cause a suppression of the 

 phenomena of development. 



Moore, Roaf and Whitley ('05) worked upon the effects of 

 alkalies and acids and of alkahne and acid salts upon growth 

 and cell division in the fertilized eggs of Echinus esctdentus. 

 The bases used were NaOH, KOH, Ca(0H)2, and NH4OH. 

 The acids were HCl, CH3COOH, and CO2, and the salts NaaCOs, 

 NaHCOs, Na2HP04, and NaH2P04. These workers found that 

 bases, except NH4OH, give acceleration of development in low con- 

 centrations, while higher concentrations check development, and 

 finally kill. Acids all inhibit. The primary factors affecting 

 the rate of growth appear to be the variations in concentration 

 of hydrogen and hydroxyl ions. Thus all of the caustic alkalies 

 are of approximately equal power, and there is little or no action 

 of the cation. But in the case of the phosphates, where the 

 hydrogen-hydroxyl ion concentrations are comparatively low. 

 there seems in addition to be a specific factor. The extreme 

 limits of variation of hydrogen and hydroxyl ion concentrations 

 within which growth is possible are shown to be very narrow,- 

 0.0015N caustic alkah or O.OOIN acid practically stopping all 

 development, Whitley ('05) showed the same relationship 

 between hydrogen-hydroxyl ion concentration and development 

 to hold for eggs of Pleuronectes platessa. He gave three reasons 

 why alkali is less harmful than acid: 



1. Alkali added to sea-water is immediately thrown out as 

 insoluble hydrates or carbonates. 



2. Alkali is constantly used up to neutralize CO2 produced by 

 the animal. 



3. Loeb has shown a low quality of alkali increases the perme- 

 ability to Oo. This may increase the resistance of the egg. 



THE JOURNAL OF EXPERIMENTAL ZOOLOGY, VOL. 30, NO. 4 



