376 



if they succeed in procuring anew living gym- 

 noti in one of the great capitals of Europe. The 

 discoveries that will be made on the electro- 

 motive apparatus of these fish, much more ener- 

 getic, and more easy to preserve, than the tor- 

 pedoes % will extend to all the phenomena of 

 muscular motion subject to the will. It will 

 perhaps be found, that, in most animals every 

 contraction of the muscular fibre is preceded 

 by a discharge from the nerve into the muscle; 

 and that the simple contact of heterogeneous 

 substances is a source of movement and of life 



* In order to investigate the phenomena of the living 

 electromotive apparatus in their greatest simplicity ; and not 

 to mistake circumstances, which depend on the degree of 

 energy of the electric organs, for general conditions ; it is 

 necessary, to perform the experiments on those electrical 

 fishes that are most easily tamed. If the gymnoti were not 

 known, we might suppose from the observations made on 

 torpedoes, that fishes cannot give their shocks from a dis- 

 tance through very thick strata of water, or through a bar of 

 iron, without forming a circuit. Mr. Williamson has felt 

 strong shocks, when he held only one hand in the. water, and 

 this hand, without touching the gymnotus,was placed between it 

 and the small fish, toward which the stroke was directed from 

 twelve or fifteen inches distance. (Phil. Trans., vol. Ixv, p. 99 

 and 108.) When the gymnotus was enfeebled (in a bad 

 state of health), the lateral shock was imperceptible j and in 

 order to feel the shock it was necessary, to form a chain, and 

 touch the fish with both hands at once. Cavendish, in his 

 ingenious experiments on an artificial torpedo, had well 

 remarked these differences, depending on the greater or less 

 energy of the charge. (Phil. Trans. 1776, p. 212.) 



