136 



ELECTRICITY AND PROTOPLASM 



[Ch. VI 



body next to the kathode, but none at the anode end. The 

 result that one obtains depends, however, to a certain extent, 

 upon the strength of the current that one employs. But Nagel 

 did not, apparently, measure his currents, so there is no cer- 

 tainty that his results can be at once duplicated. Taking the 

 results for various Invertebrates as they are given, however 



they are instructive. 



table XIII 



All the species in this table (all of which, except Ciona, are 

 MoUusca) show in their response a more or less close approach 

 to the type of Pelomyxa (excitation, rest ; rest, excitation) ; and 

 we may believe that with appropriate stimulus they would re- 

 spond in precisely that way. 



In a second class of cases the response of the whole animal 

 belongs to the katex type ; thus two species examined by 

 Nagel showed the following responses : — 



* Inconstant in occurrence. 



