16 



Papers from the Department of Marine Biology. 



while the rate of nerve-conduction is much augmented. This is, of 

 course, a striking instance of Loeb's law of the antagonism between a 

 univalent and a bivalent cation, even though the bivalent cation in this 

 case is magnesium, well known to be a depressant, especially for 

 muscular activity in Cassiopea. 



The temperature coefficient of nerve-conduction is 2.5 times as 

 great as that of the electrical conductivity of the sea-water, as appears 

 in table 6. 



The rate of nerve-conduction in Cassiopea in heated sea-water was 

 first determined by Harvey (1911) who found it to accelerate in a right- 

 line ratio up to 35° to 38° C, at which point there was an abrupt decline 

 in rate. These results were later confirmed by Mayer (1914), and Gary 

 (1916). The average of the best experiments is shown in table 6. 



Table 6. (Illustrated by figure 9.) 



The high temperature coefficient of the rate of nerve-conduction 

 suggests that we may be dealing with a chemical reaction involving a 

 compound composed of sodium, calcium, and some proteid element; 

 the degree of ionization of which is considerably affected by tempera- 

 ture in the manner suggested by W. B. Hardy (1900), Quincke (1902), 

 and Bayliss (1915).* 



Possibly, also, the negative electrical potential associated with the 

 wave of nerve-conduction may increase the surface tension of the alka- 

 line colloidal particles, thus reducing their size, rendering them more 

 soluble, and thereby increasing the concentration of the reacting ions. 



In this connection, A. Mayer, A. Schaeffer, and E. Terroine (1907)t 

 state that in a large number of alkaline organic colloids, the addition 

 of a further negative charge, in the form of OH' ions, caused a decrease 

 in the size of the particles. Moreover, Hulett (1901) J has shown that 



♦Principles of General Ph^-siology, p. 77. 



tCompt. Rendu.s Acad. Sci., Paris, tome 145, p. 919. 



jZeitschrift physik. Chemie, Bd. 37, p. 406. 



