490 FISHES. 



The first experiments of this kind were made by Mr. Walsh, of the 

 Royal Society of London, at Rochelle, in France, in the year 

 1772. 



u The effect of the torpedo,*' says Mr. Walsh, " appears to be 

 absolutely electrical, forming its circuit through the same conduc- 

 tors with electricity, and being intercepted by the same non-con- 

 ductors, as glass and sealing-wax. The back and the breast of 

 the animal appear to be in different states of electricity; I mean, 

 in particular, the upper and lower surfaces of the two assemblages 

 of pliant cylinders engraved in the work of Lorenzini*. By the 

 knowledge of this circumstance, we have been able to direct his 

 shocks, though they were small, through a circuit of four persons, 

 all feeling them; and likewise through a considerable length of 

 wire held by two insulated persons, one touching his lower sur- 

 face, and the other his upper. When the wire was exchanged for 

 glass or sealing-wax, no effect could be obtained : but as soon as 

 it was resumed, the two persons became liable to the shock. These 

 experiments have been varied many ways, and repeated, times 

 without number, and they all determined the choice of conductors 

 to be the same in the torpedo as in the Leyden phial. The sensa- 

 tions, likewise, occasioned by the one and the other, in the human 

 frame, are precisely similar. Not only the shock, but the numb- 

 ing sensation, which the animal sometimes dispenses, expressed in 

 French by the words engourdissement and fourmillement, may 

 be exactly imitated with the phial, by means of Lane's electrome- 

 ter : the regulating rod of which, to produce the latter effect, 

 must be brought almost into contact with the prime conductor 

 which joins the phial. It is a singularity that the torpedo, when 

 insulated, should be able to give us, insulated likewise, forty or 

 fifty successive shocks, from nearly the same part ; and these, with 

 little, if any, diminution of their force. Each effort of the 

 animal, to give the shock, is conveniently accompanied by a de- 

 pression of the eyes, by which even his attempts to give it to non- 

 conductors can be observed : in respect to the rest of his body, he 

 is in a great degree motionless, though not entirely so. I have 

 takeu no less than fifty of the above mentioned successive shocks, 

 from an insulated torpedo, in the space of a minute and a half. 



* Observazioni intorno alle torpedini. 1768. 



