120 



tenth of an inch in diameter, weighing only four grains and a half, 

 and being contained in a glass tube just large enough to receive it. 

 On the electric discharges from a vigorous torpedo being made to 

 pass through the wire during a few minutes, the needles were ren- 

 dered strongly magnetic. The same influence transmitted through 

 the wires of the multiplier produced very decided deflexion of the 

 needle; the under surface of the electrical organ of the torpedo 

 corresponding in its effect to the zinc plate of the simple voltaic 

 circle, and the upper surface corresponding to the copper plate. No 

 effect of ignition could be perceived when the discharge from the 

 torpedo was made to pass through a silver wire one thousandth of 

 an inch in diameter: nor could unequivocal evidence be obtained of 

 the production of sparks on interrupting the circuit ; the slight lu- 

 minous appearances which occurred being probably of the same kind 

 as those often exhibited by sea water when agitated. A small gold 

 chain, however, composed of sixty double links, was found to be 

 capable of transmitting the shock ; a fact which seems to show that 

 air is not impermeable to the electricity of the torpedo. When 

 fine silver wires, interrupted by a solution of common salt, were 

 placed in the circuit, minute bubbles of air collected round the point 

 communicating with the under side of the torpedo, but none at the 

 other point. When gold wires, instead of the silver ones, were 

 used, gas was evolved from each of the extremities ; but in greatest 

 quantity, and in smaller bubbles, from the lower, than from the upper 

 wire. With a strong solution of nitrate of silver, the point of the 

 lower gold wire became black, and only two or three bubbles arose 

 from it ; the point of the upper gold wire remaining bright, and being 

 surrounded with many bubbles. Similar, but less distinct, results were 

 obtained by employing a strong solution of superacetate of lead. 



The remainder of the paper is occupied with a detailed account 

 of the anatomical structure of the electrical organs of the torpedo, 

 and of the muscles that surround them. The texture of the co- 

 lumnar portions of those organs appears to be homogeneous, with 

 the exception of a few fibres, probably branches of nerves, which 

 pass into them. A large quantity of water, separable by evapora- 

 tion, enters into their composition: and they undergo spontaneous 

 changes more slowly than the muscles. They are incapable of con- 

 traction by any of the ordinary stimuli, and even that of an electric 

 shock from a voltaic battery, applied either to the organs themselves 

 or to the nerves which supply them. Hence the conclusion is 

 drawn that these organs are not muscular, but that their columns 

 are formed by tendinous and nervous fibres, distended by a thin ge- 

 latinous fluid. 



The anatomical account is concluded by a description of the 

 origin, course, and distribution of the nerves belonging to the elec- 

 trical organs. The author found that the gastric nerves are derived 

 from these; and hazards the conjecture that superfluous electricity 

 may, when not required for the defence of the animal, be directed 

 to the stomach, so as to promote digestion : in corroboration of 

 which he cites the instance of a torpedo which, when living-, had 



