Relations of the Nervous and Electric Forces. 369 



ment. Thus the very conducting power which the water 

 has ; that which it gives to the moistened skin of the fish or 

 animal to be struck ; the extent of surface by which the fish 

 and the water conducting the charge to it are in contact; all 

 conduce to favour and increase the shock upon the doomed 

 animal, and are in the most perfect contrast with the ineffi- 

 cient state of things which would exist if the gymnotus and 

 the fish were surrounded by air ; and at the same time that 

 the power is one of low intensity, so that a dry skin wards it 

 off, though a moist one conducts it (1760.): sojis it one of 

 great quantity (1770.), that though the surrounding water 

 does conduct away much, enough to produce a full effect may 

 take its course through the body of the fish that is to be 

 caught for food, or the enemy that is to be conquered. 



1787. Another remarkable result of the relation of the 

 gymnotus and its prey to the medium around them is, that 

 the larger the fish to be killed or stunned, the greater will 

 be the shock to which it is subject, though the gymnotus 

 may exert only an equal power ; for the large fish has pass- 

 ing through its body those currents of electricity, which, in 

 the case of a smaller one, would have been conveyed harm- 

 less by the water at its sides. 



1788. The gymnotus appears to be sensible when he has 

 shocked an animal, being made conscious of it, probably, by 

 the mechanical impulse he receives, caused by the spasms into 

 which it is thrown. When I touched him with my hands, 

 he gave me shock after shock ; but when I touched him with 

 glass rods, or the insulated conductors, he gave one or two 

 shocks, felt by others having their hands in at a distance, 

 but then ceased to exert the influence, as if made aware it 

 had not the desired effect. Again, when he has been touched 

 with the conductors several times, for experiments on the 

 galvanometer or other apparatus, and appears to be languid 

 or indifferent, and not willing to give shocks, yet being touch- 

 ed by the hands, they, by convulsive motion, have informed 

 him that a sensitive thing was present, and he has quickly 

 shown his power and his willingness to astonish the experi- 

 menter. 



1789. It has been remarked by Geoffroy St. Hilaire, that 

 the electric organs of the Torpedo, Gymnotus, and si- 

 milar fishes, cannot be considered as essentially connected 

 with those which are of high and direct importance to the 

 life of the animal, but to belong rather to the common tegu- 

 ments ; and it has also been found that such Torpedos as 

 have been deprived of the use of their peculiar organs, have 

 continued the functions of life quite as well as those in which 



Phil. Mag. S. 3. Vol. 15. No. 97. Nov, 1839. 2 B 



