ELEMENTARY VITAL PHENOMENA 



269 



organs are developed in the electric fishes for the production 

 of electricity alone. It is most interesting that these electric 



Fig. 122. — Non-polarisable electrodes. 1. Two non-polarisable electrodes laid upon an excised 

 gastrocnemius muscle of the frog. //. A non-polarisable electrode in its stand. 



organs have the same embryonic origin as cross-striated muscles, 

 to which also in their adult state they possess great similarity. 



Fig. 123. — /. Torpedo marmoratus ; the skin is partially cut away so that the electric organ, a, is 

 visible ; it consists of numerous polygonal columns, which are here seen in cross-section. 

 (After Ranvier.) //. Two electric columns from the torpedo seen en, face with the electric 

 nerves branching over them. (After R. Wagner.) 



The electric organ of the torpedo is composed of numerous 

 long columns, hexagonal in cross-section, which correspond to 



