Nerve-Conduction in Cassiopea Xamachana. 



13 



we shall show, appears to be directly proportional to the concentration 

 of the surrounding cations of sodium, potassium, and calcium, mag- 

 nesium taking an almost negative part in the control of rate of nerve- 

 conduction in diluted sea-water. 



Table 5 (illustrated by fig. 8) shows the rates of nerve-conduction in 

 Cassiopea in Tortugas sea-water diluted with aerated, alkaline distilled 

 water having a hydrogen-ion concentration of 1.17X10" 8 , or 7.93 P H . 



TABLE 5. 



120 



33 32 31 



30 29 28 27 



Temperature 



26 25 24 Z3 



FIG. 9. Showing that the temperature coefficient for the rate of nerve-con- 

 duction in Cassiopea is 2.5 times as great as that of the electrical 

 conductivity of the sea-water. 



The close resemblance between the decline in rate of nerve-conduc- 

 tion and the corresponding decline in electrical conductivity of the 

 surrounding sea-water suggests but does not prove that the two phe- 

 nomena are directly dependent one upon the other; but as we shall show 

 later, this seems doubtful. 



