368 



often observed the same phenomenon in galvan- 

 izing frogs. 



The torpedo moves the pectoral fins convul- 

 sively, every time it emits a stroke; and this 

 stroke is more or less painful, according as the 

 immediate contact takes place by a greater or 

 less surface. We have above observed, that the 

 gymnotus gives the strongest shocks without 

 making any movement with the eyes, head, or 

 fins*. Is this difference caused by the position 

 of the electric organ, which is not double in the 

 gymnoti ? or, does the movement of the pectoral 

 fins of the torpedo directly prove, that the fish 

 restores the electrical equilibrium by it's own 

 skin, discharges itself by it's own body, and that 

 we generally feel only the effect of a lateral 

 shock ? 



We cannot discharge at will either a torpedo 

 or a gymnotus, as we discharge at will a Leyden 

 vial or a Voltaic pile. A shock is not always 

 felt, even in touching the electric fish with both 

 hands. We must irritate it, to make it give 

 the shock. This action in the torpedoes, as well 

 as in the gymnoti, is a vital action ; it depends 

 on the will only of the animal, which perhaps 

 does not always keep it's electrical organs 



* The anal fin of the gymnoti only has a sensible motion, 

 when these fishes are excited under the belly, where the elec- 

 tric organ is placed. 



