128 REPORTS ON INVESTIGATIONS AND PROJECTS. 



REPORTS OF INVESTIGATORS. 



The Permeability of Living Cells for Alkalies, by B. Nezvton Harvey, 

 Princeton University. 



THE PERMEABILITY OF CEEES FOR ALKALIES. 



The use of neutral red as an indicator within the cell affords so delicate a 

 means of detecting the presence of the hydroxyl ion that I have continued 

 my studies on the permeability of cells for alkalies, a research begun at Tor- 

 tugas in 1910. My aim has been to determine the time relation between the 

 color change of the indicator and the observed change in appearance or in 

 functional activity of the cell produced by representative alkalies. The mus- 

 cle-nerve tissue of Cassiopea xamachana, the muscles of Salpa, of the tenta- 

 cles of Pennaria and marine annelids, the swimming-plates of the ctenophore 

 Beroe, the ciliated cells of trochopores and larvse, and the eggs of many ma- 

 rine animals may be employed to determine the above relation. Only a small 

 amount of alkali can be added to sea-water without precipitating the mag- 

 nesium, so that a Mg-free sea-water was used to dissolve the alkali. Mg-f ree 

 sea-water is a fairly well-balanced medium for marine tissues. 



Preliminary studies on the permeability relations of marine animals for 

 ammonia, the amines, and inorganic hydroxides confirmed, in practically 

 every detail, previous results obtained with plant cells and Paramcecium. 

 The eggs of H olothuria Horidana, Hipponoe esculenta, Pomatostegus stella- 

 tus, Toxopneustes variegatus, and Eunice fucata, the gonads and subum- 

 brella epithelium of Cassiopea xamachana, the tentacles of Sabella, and the 

 respiratory tree tissues of Holothuria Horidana, if stained in neutral red, are 

 all entered very rapidly (one-half minute to 5 minutes) by ammonia, methyl, 

 dimethyl, trimethyl, ethyl, propyl, and isopropyl amines (N/250 to N/500), 

 but not by tetraethyl ammonium hydroxide, NaOH, KOH, or Sr(OH)2 

 (>/^ hour). If che tissues are replaced in sea-water after decolorization 

 in the amines or ammonia, the red color returns, providing the cells are not 

 so small that the free neutral red base has had time to diffuse out. The color 

 return is markedly more rapid in ammonia and trimethyl amine. These two 

 substances are considerably weaker bases than the rest of the amines and 

 they are correspondingly less toxic, as the following experiments indicate. 



If unfertilized Toxopneustes eggs are placed in N/250 solutions of ammo- 

 nia, the amines, and N(C2H5)40H for two minutes, then returned to sea- 

 water and fertilized, the eggs in all solutions begin to develop and segment, 

 some irregularly, although the decolorization is instantaneous in all solutions 

 (except N(C2H5)40H). If returned to sea- water after 5 minutes only un- 

 segmented eggs and fragments are found in the dishes of eggs treated with 

 methyl, dimethyl, ethyl, and propyl amines, a few irregular segmentations in 

 isopropyl amine, but numerous segmentated eggs in ammonium hydrate, tri- 

 methyl amine, and N(CoHr,)40H. Eggs left permanently in solutions of 

 the latter three alkalies cytolyze much less readily than eggs left in solutions 

 of the remaining amines. N(C2H5)40E[ behaves in every respect like the 

 inorganic hydroxides and may be taken as a representative of that class in 

 the above experiment. 



The same relations hold good for the epithelio-muscle tissue of the sub- 

 umbrella surface of Cassiopea xamachana. The granules which stain are 

 probably mucous globules, although a minute histological examination will be 

 necessary to determine the exact relations of these granules to the individual 

 epithelial, nerve, and muscle cells. They are situated in the outer third (away 



