On the Anatomy of Vcgetallcf. 



panned brings; it covers the nafcent embryo,, and the_indi r 

 vidual which has arrived at the (late of decrepitude; it fol- 

 lows all the fmuofitks W Indies, penetrates into their cavities^ 

 and protects the mofKhiicate parts : thus in animals, alter 

 enveloping all the external parts, comprehending even the 

 globe of the eye, it isfeen falling back on the lips, penetrat- 

 ing into the inteflinal canal, into the- noftrils, and the au- 

 ditory pafTage ; and in plants, it covers the Hems, branches, 

 leaves, flowers and fruits. The epidermis (add they) is not 

 imiilar in every part of the fame being : fome times it is exceed- 

 ingly fine, and fometimes it avfumes more confidence; but in 

 alf cafes it is colourlefs and tra'nfparent. If it appears white on 

 the trunk of the birch-tree, and brown on the young branches, 

 afh-gray on the plum-tree, red and argenteous on the cher- 

 ry-tree, green on the voung moots of the almond-tree, and 

 afh-coloured on the old ones ; this difference depends merely 

 on the : colour of the fub fiances it covers, in the fame manner 

 as the white, black, and copper colour of the white, negro or 

 caffre depend on the colour of the mucous body. By follow- 

 ing this comparifon, a new point of fimilitude is thought to 

 be obferved in the dilatability of the epidermis of animals and 

 plants : it yields to all development, and extends in propor- 

 tion as the being grows : it embraces only a fmall furface itt 

 the foetus of the animal, but it dilates inienfibly and covers 

 a much greater furface when the animal attains to its utmofl 

 growth. It is thus that the epidermis which covers the feeds 

 of plants dilates and yields to the incrcafe of the fruit, and 

 that the epidermis which covers the embryo viclds alfo to the 

 increafe of trees. The extenflon of this membrane will be 

 found to be prodigious, when we confider \Vhat the gourd was 

 before its flower withered, and what the oak was when e 

 cealed in the acorri. But, as there are certain animals the 

 old epidermis of which detaches itfelf, ' and at the end of a 

 certain time gives place to. another; in the fame manner there 

 are certain vegetables which throw off their epidermis in or- 

 der to affume a new one. Tt is obferved that the epidermis 

 of the trunk and branches of the plane-tree detaches itfelf in 

 fcrolls like that of oviparous quadrupeds. 



Thefe companions, no doubt ingenious, are far from be'fng 

 exacT in every point. It may even be. faid that they are 

 founded on imperfect obfervations. To be convinced of this, 

 it will be fufficient to reflect on the" definition we have given, 

 of the epidermis of vegetables. This membrane is nothing 

 but the exterior union of the cells of the circumference, and 

 differs from the membranes which form the other fides only 

 by the changes occafloned by its polition. If it is lefs tranf- 



Vol. XIII. No. 51. Q parent,. 



