51 



bark is necessary to the life and growth of 

 the tree. There can be no doubt, however, 

 that the tree receives its increment chiefly 

 from the juices circulating between the 

 wood and periligneum ; for we observe that 

 a new ting or stratum of wood is added 

 every year to the circumference of the old 

 wood : how this is done, is more difficult to 

 understand ; but we know that solids are 

 formed from water and the finest fluids, by 

 a deposition of minute particles, as in petri- 

 faction and ossification, and it is highly pro- 

 bable that the wood is formed in the same 

 manner, the old wood serving as a nucleus. 



I had observed the bark crack and rend 

 in a thousand places, which I could not 

 conceive to be any thing but an effort of 

 nature to throw off an incumbrance. 



