Penetration of Marine Tissues by Alkali. 



135 



Table 2. Effect of ammonia, amines, and tetraethylammonium hydroxide on toxopneustes 



eggs, stained in neutral red. 



I. Control fertilized in Mg-free sea-water red, segmentations normal. 

 II. Control unfertilized in Mg-free sea- water red, unsegmented, normal. 



It will be noticed that eggs are not cytolyzed after 3 hours immersion 

 in N/250 NH4OH, NH(CH3)30H, and N(C2H5)40H (column 3) and after 

 5 minutes immersion are still capable of fertilization (column 5) ; whereas 

 the opposite is true of the remaining alkalies of table 2. N(C2H5)40H, most 

 highly dissociated of all, is no more toxic than NH4OH, least dissociated of 

 all. The explanation of the difference must lie in the penetrating powers 

 of the two alkalies. N(C2H5)40H can not penetrate the egg-surface and 

 is consequently less toxic than NH4OH, which readily penetrates. Pene- 

 tration is of first importance in determining toxicity. If the alkali pene- 

 trates readily, then degree of dissociation is a further factor in determining 

 toxicity. Those weak (ammonia and trimethylamine) alkalies which are 

 least dissociated are least toxic. 



The same fact appears when other cells are tested; for if segmenting 

 palolo eggs {Eunice jucata) are placed in N/250 solutions of NHiOH and the 

 amines for two minutes, and then returned to sea-water, only those eggs 

 develop into swimming larvae which have been immersed in trimethylamine 

 and ammonia. Eggs exposed to the remaining amines are for the most part 

 killed; only a few larvae develop. 



GENERAL CONSIDERATIONS. 



On being returned to sea-water the palolo eggs which have been turned 

 yellow by immersion in the weak alkalies again become red in color. The 

 return of color is much more rapid in ammonia and trimethylamine than in 

 the remaining amines. The explanation of this phenomenon lies in the lesser 

 degree of dissociation of the former substances. Neutral red occurs in the 

 egg in small granules, a combination between the neutral red base (BOH) 

 and some organic substance having acid properties (HA), forming a salt (BA). 



BOH -j- HA = BA -f- H2O 



