I 



111 On the Regeneration of certain Paris of Fijhes» 



fiib, have their Ikeleton on the outfide, Having cut the right fin of the 

 that is to fay, their foft parts are cover- brcaft of a gold fifh, in the fpace of 

 ed with a hard fubltance. In others, eight months that part became as large 

 on tht". contrary, fuch as the lizard, as the left, which I had not touched, 

 the falamander, kc. the Ikeleton is in I repeated this operation on the fins of 

 the infide, that is to ."ay, the bony the belly, and ihe refult was always 

 )art is covered by the parts that are the fame. It is true that though the 

 bft. new fins were as large as the old, they 



It is well known that cray-filh, the remained fome time white, and lefa 

 parts of which are joined to the body tranfparent than the red. 

 by very delicatearriculations, are liable I made oblique fe*5tions tranfverfely, 

 to lofe them, but that new ones grow and, in a word, in every direction, 

 np at the end of fome weeks. in the tail fin of different fifiies, and 



The reprodu(flion of the paws of the parts cut alway-> regenerated at the 

 falamanders has been traced with the end of a certain time. Fifhes fub- 

 greatelt minutenefs, by twoof the moft jeded to thefe experiments loft their 

 diftinguifhed obfervers of the prefent equilibrium, and their progrelfive fa- 

 age, Mr. Bonnet of Geneva, and Mr. culty became lefs in proportion as I cut 

 Spallanzani. We are indebted to thefe their fins. They never recovered 

 gentlemen for a number of difcoveries their natural pofition until thefe parts 

 in one of the moft curious points of were renewed. 



phvfiology. The regeneration, how- From fome fifhes I cut off the fins 

 ever, of articulate parts, has not been as near to the body as poffible ; thefe 

 much examined in fifhes, a kind of animals were then unable to keep them- 

 animals very different from thofevvhich felves horrizontally in the water, 

 have been already obferved, and of Their heads inclined to the bottom of 

 which the blood is never above two the vefTel; they wavered, and could 

 or three degrees warmer than the ele- not, but with great exertion, refumc 

 nient they inhabit. an horizontal pofition. Their fins 



I have cut certain portions from the grew up very flowly. 

 fins of different fifnes, and having re- The fame experiments having been 

 peated this experiment at various repeated on feveral fifhes, I always 

 epochs, I have always found that thefe obferved the fame effeds. In a carp, 

 parts reproduced themfelves nearly, which had the edges of its fins gnawed 

 It appeared to me, that they grow up by fmall iifhes, in fuch a manner, that 

 quicker in fifties that are young, and they appeared to be fringed, I per- 

 in fome fpecies rather than in others, ceived, at the end of fome months. 

 Having cut away part of the fins of that the edges were become perfedly 

 fome gold fifh, I obferved the third day fmooth. 



on the edge which had been cut, a I rem.arked that the fins were rencw- 



kind of whitilh excrefcence ; on the ed generally fooner or later, according 



eighth this cxcrefence was fenfibly ex- as they were more or lefs ufeful to the 



tended, and it foon became a mem- animal. Mr. Spallanzani made a fimilar 



brane, which at firft was only aline obfervation on earth worms, the heads 



in breadth. This membrane was of which were conftantly reproduced 



thicker than that which formed the fooner than the pofterior part of the 



bottom part of the fin, but in proper- body : in the like manner, in fiflies, the 



tion, as it extended itfelf, it became tail fin, the moft ufeful of all, fince it 



thinner, and tranfparent. At the end enables them to execute almoft all 



of three months I could diftinguifh their motions, was always formed 



the formation of the bony ribs, def- fooner than thofe of the belly or the 



tined to fupport this membrane, breaft ; and thofe which are deftined to 



They appeared to be a continuation fupport the fifti at anequal height, and 



of the griftles of the bafe. They at firft to aid it in its lateral motions, were 



feemed to be of a fubll:ance like jelly, renewed much fooner than thofe of 



the 



