456 PROSE HAi;iEUTICS. 



asked why it m.akes people sleep, responds, ' Quia est in 

 eo virtus dormitiva ;' so Galen gravely teUs us the tor- 

 pedo affects by a torporific action peculiar to itself! Of 

 all ancient speculations, that of the Arabian physician, 

 Averrhoes, comes nearest to the right explanation of the 

 phenomenon. He says, ' The power which this fish pos- 

 sesses of affecting, the ^kin, seems to be of a kind analo- 

 gous to that by which the magnet acts upon steel ;' and 

 as magnetism is close akia to, if not identical with elec- 

 tricity, this comes very near the truth, and is, in fact, a 

 suspicion in anticipation of Dr. Bancroft's, of the iden- 

 tity of the electric fluid and that of the narke, which 

 has been since fully confirmed by Mr. Walsh in his ex- 

 periment at La Rochelle.* Singular as is the pheno- 

 menon of such a power residing in a fish, the absolute 

 control which the creature has of using or forbearing to 

 use it is not less remarkable. Experimenters know well 

 that unless the narke be in a commimicative frame of 

 mind as well as body, though ever so much teased and 

 tormented, she will ' die and make no sign.^ In accord- 

 ance with this we were not able, during a long sojourn at 

 Naples, to obtain one shock in our own person ; while 

 many lazzarone frientis who did not seek it, had frequently 

 their arms ' astonished' (the word is Reaumur's) for a 

 whole day after lugging a narke on board. That she can 



* Having mounted a circle of bis friends upon glass stools, 

 and taken the other necessary precautions to isolate them pro- 

 perly, Mr. Walsh stirred up the ire of the narke by poking him 

 about. Mid then apphed the connecting wires ; the aura traversed 

 along the hne, and gave each friend standing at the table a con- 

 clusive and satisfactory shock. But though the near affinity of 

 the battery of this ray with an ordinary galvanic battery is thus 

 apparent, it is a singular circumstance that no sparks have been 

 as yet ahcited from the body of "the fish, and that even whilst it 

 is in faction light bodies suspended near are not repeUed, as, under 

 the same circumstances, they would be over a Leyden jar, an elec- 

 tric machine, or a horse-shoe magnet. 



