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a fmall part of the bark is alive, and that is what is next to the tree. 

 But the cafe is otherwile, with regard to the bark of trees, where 

 the veflels forming it, take a circular courfe round the tree ; for 

 when the trees increafe in fize, thefe veflels cannot feparate afunder, 

 but break ; whereupon, the old bark is feparated from the new 

 and falls off, for which reafon, fuch trees have always a thin bark, 

 and this is plainly to be feen in the birch. 



And in like manner as it has been faid, that the barks of trees 

 are formed and nourilhed, not from the root, but the wood, and 

 that for tlie fame reafon, the bark is not formed in branchings. The 

 fame I alfo confider to be the cafe, in the produclion and nou- 

 rifliment of the real fkin of our bodies, which is covered by an 

 upper Ikin compofed of Scales ; for having examined the Ikin of fe- 

 veral animals, I obferved, that in its texture it was not produced ir- 

 regularly, but I mufl; confefs, that the texture of the true Ikin was, 

 throughout, an entire uniform body ; and I alfo imagined, that all 

 the veflels (excepting the arteries, veins, and nerves), of which 

 our true Ikin is compofed, do run one among another in a Monder- 

 ful manner to form a Ikin which Ihall be of extraordinary ftrcngth ; 

 and that at length they grow thitmer and thinner, till at their ex- 

 tremities, they form Scales, with which the Ikin is covered, and then 

 thefe very thin veflels have no other termination than by being 

 formed into Scales, fo that each Scale confifls of as many veflels as 

 there were extremities compofmg the Scale, and that each Scale re- 

 mains united to the veflels until a new Scale is formed under it.. 





