

SUPPOSED MAGNETIC PHENOMENA. 129 



would be but a feeble part of the stroke which re-establishea 

 the equilibrium in the interior of the fish.* As the gym- 

 notus directs its stroke wherever it pleases, it must also be 

 admitted that the discharge is not made by the whole skin 

 at once, but that the animal, excited perhaps by the motion 

 of a fluid poured into one part of the cellular membrane, 

 establishes at will the communication between its organs 

 and some particular part of the skin. It may be conceived 

 that a lateral stroke, out of the direct current, must become 

 imperceptible under the two conditions of a very weak 

 discharge, or a very great obstacle presented by the nature 

 and length of the conductor. Notwithstanding these con- 

 siderations, it appears to me very surprising that shocks 

 of the torpedo, strong in appearance, are not propagated 

 to the hand when a very thin plate of metal is interposed 

 betweeu it and the fish. 



Schilling declared that the gymnotus approached the 

 magnet involuntarily. We tried in a thousand ways this 

 supposed influence of the magnet on the electrical organs, 

 without having ever observed any sensible effect. The fish 

 no more approached the magnet, than a bar of iron not 

 magnetic. Iron-filings, thrown on its back, remained motion- 

 less. 



The gymnoti, which are objects of curiosity and of the 

 the deepest interest to the philosophers of Europe, are #t 

 once dreaded and detested by the natvies. They famish, 

 indeed, in their muscular flesh, pretty good aliment; but 

 the electric organ fills the greater part of their body, and 

 this organ is slimy, and disagreeable to the taste; it is 



* The heterogeneous poles of the double electrical organs must 

 exist ia each organ. Mr. Todd has recently proved, by experiments 

 made on torpedos at the Cape of Good Hope, that the animal continues 

 to give violent shocks when one of these organs is extirpated. On the 

 contrary, all electrical action is stopped (and this point, as elucidated by 

 Galvani, is of the greatest importance) if injury be inflicted on the 

 brain, or if the nerves which supply the plates of the electrical organs be 

 divided. In the latter case, the nerves being cut, and the brain left un- 

 touched, the torpedo continues to live, and perform every muscular 

 movement. A fish, exhausted by too numerous electrical discharges, 

 iuffered much more than another fish deprived, by dividing the nerves, 

 of any communication between the brain and the electromotive apparatus. 

 (Philosophical Transactions, 1816). 



VOL. II. X 



