194 ELECTRIC FISHES. LiECT. X. 



non is repeated. By the aid of this instrument we are 

 enabled to prove that, in the discharge of the torpedo, the 

 current is directed in the galvanometer from the back to the 

 belly of the fish, so that the back represents the positive 

 pole, and the belly the negative pole of the pile. If, by 

 means of the extremity of the wires of the galvanometer, 

 we examine different parts of the body of the torpedo at 

 the moment when the discharge takes place, we perceive, 

 in a manner still more evident than when frogs are used, 

 that, at the commencement of the experiment, the signs of 

 the current are obtained, by establishing the circuit between 

 any part of the back and of the belly ; but when the animal 

 has become weakened, it is necessary fop those parts of the 

 body which correspond to the points called the electric 

 organs, to be touched, in order that the existence of the 

 current may be made manifest. 



Fig, 12. 



Torpedo with one of its Electric Organs exposed. 



It is curious to observe that, by simultaneously touching 

 two points. of either the abdominal or dorsal surface of one 



