WOOD AND BARK OF TREES. 
91 
but in these they assist in forcing up the plant, keeping the 
vessels extended that the flower may not be injured, as I shall 
shew in rpy next. It is inconceivable by how many marks these Two grand 
two grand divisions in nature are indelibly fixed. I r 
divisions in 
the vegetable 
between trees and herbaceous plants, &c. their whole formation world 
appears different, not only do the latter form the bud in another 
part, but their whole existence (the root excepted) is but the 
growth of a year j but this laboratory also in a contrary direc- 
tion. In trees and shrubs, it must be at the bottom of the 
flower stem, for there all the pieces must be prepared and con- 
cocted, and its vessels arranged for the different parts they are 
to compose } but in plants that form their bud in the root, the 
laboratory can be no where but in the root alone. T promise 
myself the greatest pleasure in a most exact investigation of that, 
part. I have already near a hundred different roots with their 
flowers as they appear in the solar microscope ; but I wish also 
to give a specimen of them as they rise in the wood vessel, and 
shew how the spiral wire winds round it to keep it open 
But dissection has done more for us than shewing the 
origin of the flower bud ; it has also taughc us from whence the 
leaf buds proceed, and proved how extraordinary the difference 
exemplified between the two, which will lead me to my Last 
observations on the bark. The leaf bud (as I have before shewn) Where first 
is formed of the juices of the bark and the elongation of its vessels, 8 rowin K* 
it never touches the wood, except receiving the few nourishing 
vessels that run into it ; nor proceeds further in the interior, than 
the inner bark where it is engendered, and remains till bursting 
out into leaf ; and all the purposes nature seems desirous to effect, 
by its various precautions, is keeping the juices separate, the sap 
from entering the precincts of the bark, and the bark liquid from 
reaching the wood : and the more to effect the separation, all the 
trees that have a superabundance of bark juice, are di- 
vided by a curtain which preserves them from this mutual 
contamination. Now, we are well acquainted with the soften- Matter sotten- 
....... . .. . , ed by the bark 
ing power of the bark juices — does it not strike the mind, j u i ces . 
that this piece must be placed in such a situation to prevent the 
alburnum from being injured, and the wood from being sof- 
tened and destroyed by its reducing powers ? But if this idea 
strikes the imagination, how much more must it convince the 
judgment, on examining the matter so applied, and finding, 
that 
