550 EDMUND NEWTON HARVEY 



^N_ NaOH In 

 0.6 m NaCl. 



Fertilized eggs (4 minutes after fertilization) 



Fertilized eggs (20 minutes after fertilization) 



Unfertilized eggs (control) 



Unfertilized eggs (5 minutes after acetic treatment) . 



15 

 20 

 30 

 20 



Contrary to the results obtained in the Toxopneustes experi- 

 ment it will be noted that the starfish eggs did not regain their 

 original resistance to NaOH a short time after fertilization. 



While it is of course true that in time NaOH may eater sea 

 urchin eggs as well as Paramoecium or plant cells, and in this 

 sense they are difficultly permeable, it seems better, in consider- 

 ing the inorganic alkalies and N(C2H5)40H, to speak of a re- 

 sistance of the cell against their entrance rather than a permea- 

 bility of the cell for alkalies as I have done in a preliminary re- 

 port ('10). The change undergone at the time of fertilization 

 results in a surface less resistant to the penetration of alkali. 

 At the same time the decrease in resistance for alkali is presum- 

 ably connected with an increases in permeability for other sub- 

 stances notably the salts of sea water, as indicated by the experi- 

 ments of McClendon Cll) and Lyon ('10). 



In working with Elodea Cp. 539) I was able to show that small 

 concentrations of chloroform which inhibited the protoplasmic 

 rotation, but without any irreversible changes, increased the rate 

 with which NaOH entered the cells. Exactly the same fact may 

 be shown for the sea urchin's egg as the following experiment 

 indicates. Unfertilized Hipponoe eggs stained in neutral red 

 were placed in these solutions. 



A. 3^0 NaOH, J saturated with chloroform, in | m NaCl. 



B. 3I5 NaOH in f m NaCl. 



C. I saturated chloroform in f m NaCl. 



D. -3^0 NaOH, I saturated with ether, in | m NaCl. 



E. I saturated solution of ether in f m NaCl. 



In solution A the alkali has turned the eggs yellow in 10 minutes, 

 in D in 6 minutes and in B in 20 minutes. Eggs in the chloroform 



