Microscopical Essays. 655 



procefs of vegetation ; trie part which covers the root has the 

 raoft important offices affigned to it. 



Many are of opinion that the rind is formed of dried veficula ; 

 and Malphigi fays, that we may fee in the vafcular texture of the 

 bark of the cherry and plumb trees an arrangement of the parts 

 proper to form the rind, and this arrangement is occafioned by 

 the endeavour of the vafcular part to extend itfelf to the circum- 

 ference, and'the refiftance it meets with from the rind • and that 

 hence the veffels are flattened,, and affume a membranaceous 

 form.. 



The rind is a general" covering to the. young trunks of trees, to 

 the branches, the roots, the leaves, the fruit, the flowers, Sec. 

 Upon the trunks of large trees fome pieces only of the rind are to 

 be found, having probably been broke by the increafed fize of 

 the tree. The rind of fome (pedes of trees will bear being 

 ffretched much further than thofe of others, and remain for a 

 confiderable time uniformly fpread over the bark. Duhainel 

 afferts, that the rind of vigorous healthy trees remains longer 

 whole than on thofe that are more languid, notwithftanding that 

 the growth of the laft is flower, and therefore makes lefs efforts 

 againfl the rind. This circumflance is much in favour of the 

 difcinft organization of the rind, and againfl the opinion of thofe 

 who only fuppofe it to confiff of dried bladders. 



Thin as the rind is, it is formed of many coats, adhering clofelv 

 to each other, which in fome fpecies may be feparated with eafe, 

 in others with difficulty. Duhamel fays, that he has divided the 



