370 



i 



gymnotus, the latter giving his strokes through 

 an iron rod several feet long. 



When the torpedo is placed on a metallic 

 plate of very little thickness, so that the plate 

 touches the inferior surface of the organs, the 

 hand that supports the plate never feels any 

 shock, though another insulated person excites 

 the animal, and the convulsive movement of the 

 pectoral fins denotes the strongest and most 

 reiterated discharges. 



If, on the contrary, a person support the tor- 

 pedo, placed upon a metallic plate, with the 

 left hand, as in the foregoing experiment ; and 

 the same person touch the superior surface of 

 the electrical organ with the right hand, a 

 strong shock is then felt in both arms. The 

 sensation is the same, when the fish is placed 

 between two metallic plates, the edges of which 

 do not touch, and the person applies both hands 

 at once to these plates. The interposition of 

 one metallic plate prevents the communication, 

 if that plate be touched with one hand only, 

 while the interposition of two metallic plates 

 does not prevent the shock, when both hands 

 are applied. In the latter case, it cannot be 

 doubted, that the circulation of the fluid is es- 

 tablished by the two arms. 



If, in this situation of the fish between two 

 plates, there exist any immediate communica- 



r 



