134 Conparaiive Anato^ny of the JjlcBric Organs of the 



of the nerves is continued), and of non-conducling bodies, 

 fiich as the aponeurotic laniinse, extended through this niafs 

 of albumen and gelatine. What proves that it is on the 

 mcclianical arrangement of thcfe idio-ele6lric and non-elec- 

 tric elements that the properties of the torpedo depend, is the 

 exiftence of the fame parts in otlier rays, though thcfe fifhes 

 are not capable of producing the fame effe6ls. Thefe parts, 

 fimilar in regard to their intimate nature and texture, are 

 difpoftxl in a manner entirely different. The nerve of the 

 fifth pair in the rays and fquali is of a confiderable vo- 

 lume, and expands in a medium from which flows a great 

 quantity of albumiuo-gelatinous ferofity : but this gelatine 

 either is loll on the outfide by tubes which open without the 

 fkin, or is accumulated in a mafs on the fides of the bones of 

 the nofe. In the latter cafe, the gelatine, whatever be its 

 quanlitv, is of no ufe for the prodii(ition of eleftricity. This, 

 no doubt, mull be afcribed to the want of aponeurofes, which 

 divide it into fmall infulated portions — in tlie fame manner 

 as the Levdenflaflc, or the eleftric pi6lure, would fail of their 

 efi'ecl if deprived of the glafs lamjuse interpofed between the 

 metallic coalings. 



The eleitric organ, being formed of nerves and aponeurotic 

 laminae, interlarded, if I may ufe the exprelBon, with albu- 

 men and gelatine, we ought not to be allonillied at meeting 

 with it in families altogether different. All animals have 

 nerves which are lofl under the fkin ; all thofe immediately 

 below it are more or lei's provided with cellular tifl'ue : all 

 then have, in fome meafure, the rudiments of an eledric or- 

 gan. If we now fuppofe that nourifhing velVels depofit al- 

 bimicn and gelatine between the leaves of the cellular tifl'ue 

 which fixes the flcin to the exterior niufcles, we fliall eafily 

 form an idea of the manner in which this depofition may give 

 rife to the exiftence of an eleftric organ. All this may take 

 place without the influence, at leafl: in an immediate manner, 

 of the other organs effential to life. It is a development 

 which takes place almoll without the aninsal, and which has 

 no action but on the flcin and parts which depend on it; and 

 hence the re.ifon wliv fpecies which exhibit alone a develop- 

 ment fo cxiraordinarv belong, however, to a numerous genus 

 without prefenling any ftriking anomaly. 



I have tho isrlu it neceflary, for the benefit of naturalifis 

 who apply to the fiudy of natural relations, to infifl: on this 

 remark ; and I fliall tertninate this memoir by another, which 

 in my opinion mull prove interening to the learned. 



I have reafon to believe that the Arabs, at the period no 

 tloubt when they cultivated the fcicnces with fo much fuc- 



cefs, 



