NEKVK-CONDUCTION IN DILUTED AND IN CON 

 CENTRATED SEA-AYATEIl. 



By Alfred Goldsborotjgii Mayer. 



Ring-shaped strips of subiimbrella tissue of the scyphomedusa 

 Cassiopea xmnachana were deprived of marginal sense-organs and 

 placed in concentrated sea-water in order to determine the effect of 

 concentration of electrolytes upon their rate of nerve-conduction. 



These results, combined with those previously obtained^ with 

 diluted sea-water, are as follows : 



Table I. 



(Illustrated by figure 1.) 



The sea-water was concentrated by evaporation in sunlight, and 

 its alkalinity reduced to that of normal sea-water by adding a shght 

 amount of hydrochloric acid, the hydrogen-ion concentration being 

 determined colorimetrically by comparison with a graded set of thymol- 

 sulphonephthalein tubes prepared and standardized by Professor J. F. 

 AlcClendon. These readings were also checked by comparison with 

 those of a Leeds and Northrup potentiometer. 



The hydrogen-ion concentration of the sea-water at Tortugas is 

 usually between 8.1 and 8.23 P„, and many experiments made in 1917 

 showed that the rate of nerve-conduction remains practically constant 



'Mayer, A. G., 1917, Papers from Department of Marine Biologv, Carnegie Inst. Wash., vol. 

 11, I. p. 1-20. 



181 



