18 



Papers from the Deportment of Marine Biology. 



SUMMARY. 



Nerve-conduction is due to a chemical reaction involving the cations 

 of sodium, calcium, and potassium. Magnesium is non-essential. 



The probably high temperature coefficient of ionization of this ion pro- 

 teid may account in some measure for the high temperature coefficient 

 of the rate of nerve-conduction, which I find is 2.5 times as great as that 

 of the electrical conductivity of the sea-water surrounding the nerve. 



Our observations do not support the "local action" theory of R. S. 

 Lillie (1916) ; for this maintains that the rate of nerve-conduction must 



90 80 70 



Percent of diluted sea water 



60 



50 



Fig. 14. — Illustrating table 7. Results of each individual experiment 

 upon rate of nerve-conduction in Cassiopea in sea-water diluted with 

 alkaline distilled water of hydrogen-ion concentration 1.17 X10~*. 

 The heavy dotted line shows the observed average curve. 



