2. 



or three o.o. n /lC HC1 p«r 100 c.c. was found to retard davelopeont. 



Working upon th» eggs of fundulus in fresh water, Loeb found 

 that 4 o.o. n /l0 IsOH per 100 o.c. caused them to hatch factor. Mora th«n 6 c*:. 

 retarded development. 1C c.c. allowed only a few of the egge to hatch, while 

 15 c.o. resulted in failure of any to hatch. 2 o.c. of n /l0 HC1 killed all of 

 the eggs, while 1 o.c. killed most of them. Losb Attributed these results to an 

 increase of oxidation by bases and a decrease by noids. 



Later Loeb (1914) deolded that the acceleration of development of 

 the sea urchin eggs in water to which HaOH had been added did not appear until 

 the thirty-two to sixty-four cell state bsaause at first the concentration was 

 too high, but after 3 few hours the beneficial effects appeared as tha results 

 of neutralising the adds produced by tne embryos during development. Theos 

 conclusions were based upon a comparison of the rate of regeneration and growth 

 of tubularians in a solution of HsCl, KCl, CaCl2 w»d MgC^'2 in trta proportions 

 in whioh they occur in sea w:iter, and in the saaas solution to which SaOH, SaHCC3 

 or H&2 HPO4 lad been added. Althou growth was invariably better when a 



base had been added, as the effect) of the weaker bases wars better than those 

 of the HaOH, Loeb concluded that the results were not duo to the tras OH ions 

 but to tie ability of tha base to neutralise the acids produced by the tubularian. 

 Loeb and Waetney (1913 a and b) have shown that bases increase the rate of 

 oxygen consumption in both the unfertilised and fertilised egge of strongylocon- 

 trotus purpuratus but that in fertilised eggs this increase in oxygen consumption 

 is accomplished only by concentrations whicn cause a supprssiion of the phenomena 

 of development. 



floors, Roaf and Whitley (1905) worked upon the effeots of alkalies 

 and acids and of alkaline and acid salts upon growth and cell division in the 

 fertilised egge of Echinus eeoulentus. The bases used were TIaOH, KOH, Ca(0H)2 



