E X P L A I N E D BY THE MICROSCOPE.
It happens that in the Vine the Vafa interiora arc very diftind, and very beautifully PLATE
difpofed. They will be fpoken of at large in their place: but it may not be unpleafing
to the Reader to take a view of them, as they are arranged in the fubilance of the
Bark of the Vine. They are here reprefented at Fig. 5. where ijirihews the Bark, and Fig. 5.
b b the clufters of thefe veffels, keeping their regulated courfe together. b b
I'L'!:!
¡IHIIIIR
C H A P. VI.
o f t h e B l e a . .
AL T H O U G H the conftruaiorlof theBark and Rind ia Trees be verymuch the
fame, there is not that refemblancc between thefe and the next coat under^
neath; the Blea. This is the part which feparates the Bark from the Wood, and is
of a middle hardnefs between them 5 much firmer than the Bark, but fofter and
more juicy than the Wood. ' •' .
This may be feparated as the others, by maceration: and indeed whoevet propofes
to himfelf the pleafure of thefe refearches, ihould fteep a great number of Shoots of
the feveral kinds of Trees together, that where one fails another may be at hand; and
that difcovery which is withheld in one may be unfolded in another.
It is poffible, with a great deal of care, to feparate thin pieces of the Blea from the
growing Shoots of ibme kinds of Trees, in early Spring 5 but when this fucceeds the
beft it can, 'tis ilill very much inferior to the other metliod.
It may not be amifs firit to view the appearance of the Blea iri a tranfverfe feillon :
we fee that way the parts and their difpofition j and may trace them afterwards in their
conftruâion. If a piece of the Blea of common Willow be viewed in this way, we fee
that it confifts of oval apertures, and a pale but intire interftitial matter. 'Tis plain the Fig. 1.
openings are not mere holes, pierced in this intermediate fubftance -, for we fee they have
thick ûdes. They feem the efiential part of thfe whole ; the reft is only a fomething
filling up the interilitial fpaces between them, to preserve the Shoot in its form.
I f we now place before the Microfcope a thin, prepared, longitudinal piece of the Blea Fig. 2.
of the fame Willow, and apply a fomewhat larger power than in the preceding view,
we find thofe holes were the apertures of veiTels lodged in that intermediate fubftance, •
which is floccofe, white, and a mere mafs, without form. Upon examining the veffels
carefully, we lhall perceive that their coats are eompofed of this very floccofe fubftance,