49 



iosophers, about the motion of the sap 

 generally, and still some difference of 

 opinion prevails ; yet, I conceive, that part 

 of the subject, which more particularly 

 applies to the present purpose, is so far 

 obvious, that the attentive observer may 

 sufficiently satisfy himself on that head. 



If a tree were principally fed either by 

 the means of vessels in the wood or pith, 

 or both, (as some have contended,) the 

 bark might be taken off without material* 

 ly injuring it; a circumstance that never 

 happens. On the contrarjs one so tre^-t- 

 ed, always appears in a languid state 

 afterwards, if death be not the immediate 

 consequence : this may happen sooner 

 or later, according to the vigour of the 

 tree, the hardness or softness of its wood, 

 its situation as to moisture, and the sea- 

 son of the year when the bark is taken 

 off; but we do not recollect a single 

 instance where a perfect recovery has 

 been effected, whether left to nature, 

 3 



