40 



Papers from the Marine Biological Laboratory at Tortugas. 



In figure 6 the full line and open circles represent the rates in sea-water 

 diluted with 0.9 molecular dextrose, and the dotted line and black circles 

 show the rates in sea-water diluted with distilled water. 



Table 6. 



Figure 6 gives a graphic representation of the results stated in table 6, 

 the ordinates giving the average rates of the pulsating rings, and the abscissae 

 giving the relative concentration of the dissolved salts of the sea-water, 

 that of normal sea-water being loo. Thus the ordinates of the full-line 

 curve show the relative rates of conduction of the nerve-impulse when the 

 sea-water is diluted with 0.9 molecular dextrose, and the dotted curve shows 

 the same for sea-water diluted with distilled water so as to reduce its 



so 60 lU 80 SO 100 



Relative Concentration of the Sea-water Solutions. 



Fig. 6. 



osmotic pressure in nearly the same ratio as the reduced concentration of 

 the electrolytes. The practical coincidence of the curves for sea-water, 

 diluted with distilled water and with 0.9 molecular dextrose, shows that the 

 phenomena in question are not due to variations in osmotic pressure, but 

 to the varying concentrations of the electrolytes. 



Moreover, both these curves show that the most rapid rate of nerve- 

 conduction is in diluted sea-water, wherein the electrolytes are only about 



