42 



Papers from the Marine Biological Laboratory at Tortugas. 



Table 7. 



Table 8 shows the relative rates of nerve-conduction in four rings of 



Cassiopea xamachana in sea-water to which increments of 0.6 molecular 



NaCl are added. 



Table 8. 



' See fig. 7, dotted curve with determined points marked by open circles. 



Figure 7 shows the stimulating influence of sodium. The dotted curve 

 with determined points marked by open circles represents the effect of 0.6 

 molecular sodium chloride. The full-line curve shows the less marked 

 effect of 0.487 molecular sodium chloride, and the dextrose curve is intro- 

 duced for purposes of comparison. 



The average results are plotted in the upper dotted line in figure 7 and it 

 appears that the rate of the ring increases slowly in proportion as the sodium 

 becomes concentrated relatively to the other cations, until the relative 

 concentration of the sodium in respect to the other cations is about 1.48 

 times that found in natural sea-water. At still greater concentration of 

 sodium the rate declines slowly, but not so rapidly as it does in sea-water 

 diluted with a 0.9 molecular solution of dextrose, thus showing the stimu- 

 lating influence of the sodium ion. 



