164 SAKYO KANDA. 



clearly shown. Possibly the weak base NH 4 OH is more effective 

 than the stronger bases because of greater solubility in the 

 lipoids of the plasma membranes. 



14. Effects of Chemicals after Returning into Normal Sea-water. 



Lillie observed one curious effect in larvae treated with one 

 fourth and one fifth saturated solutions of chloroform in sea 

 water; when the larvae, after about two hours in corked flasks 

 containing these solutions, were poured out into watch glasses 

 the great majority were found, after three or four hours (when 

 the chloroform had evaporated), to exhibit a pronounced nega- 

 tive phototaxis in place of the usual positive. . . . l As was 

 pointed out in his previous paper, the writer found a similar 

 phenomenon in the larvae treated with sodium, potassium, cal- 

 cium and magnesium chloride solutions when they were returned 

 into normal sea-water. 2 This was particularly remarkable in 

 the larvae treated with the last two solutions during the actual 

 immersion in which there was never any reversal of positive 

 heliotropism. 



In the present experiments, the same phenomenon was also 

 found in larvae treated with salts, narcotics chloroform, chloral 

 and formalin in particular strong alkalies, potassium cyanide, 

 etc. As already shown, most of these chemicals were not favor- 

 able agents for the reversal of the positive heliotropism of the 

 larvae. Moreover, in some cases, KCN, for instance, the larvae 

 remained positive or indifferent to light while in presence of the 

 chemical substance (dissolved in normal sea-water). Never- 

 theless the "after-effect" was pronounced. That is to say, 

 almost all larvae became negative when returned to normal sea- 

 water. 



Such facts are consistent with the hypothesis that these chem- 

 icals act by changing in some way the normal properties of the 

 plasma membranes of the irritable elements concerned, so that a 

 certain time is required to recover normal conditions after return 

 to normal sea-water. 



1 Lillie, R. S., loc. cit., p. 34. 



2 Kanda, S., loc. cit. 



3 Lillie, R. S., loc. cit., p. 34. 



