yEGETABLE STRUCTURE. 79 
CHAP. XIX. 
Of the Construction of the B l e a. 
TT I T H E R T O we have feen the Coats, or conftituent fubftances of a 
Plant, limply furrounding, or plainly and uninterruptedly covering 
one the other ; but in the Blea it is much otherwife. This makes a coat 
much thicker than the reft ; but the next fubftance under this runs into it 
in various proceffes. I cannot wonder this has not been obferved, for few 
have had the attention to confider Plants in the various effeds of maceration j 
and it is only in certain ftates, tending toward decay, that this wonderful 
conftrudion can be feen. This being firft underftood, we fhall be in a 
condition to examine the conftrudion of the Blea ; by being aware of a 
different part thus mixed among it. As it is the Flefh of the Plant which 
thus runs in among the Blea, the different colour of its Juices will diftin- 
guifli it to the cautioned eye. The Juices of the Blea in Hellebore are 
mucilaginous and whitifti ; thofe of the Flefh are green and coarfe. They 
are to be feen in the Veffels making the corners of the hexagon Cells ; 
which Cells are alfo larger. 
Thus prepared, we are to examine the Blea ; and as It is a part of con- 
fiderable thicknefs, it will be beft firft to confider it In the tranfverle fec- 
tions, as in that enlarged part of the Root, Plate III. Fig. 28 ; and of the 
Flowering Stalk, Fig. 30 of the fame Plate. We find in the thicknefs of 
the Blea in thefe various parts, from fix or eight, to fourteen or more beds 
of hexagonal Cells ; and it will be proper firft: to enquire what thefe are. 
They are Membranes, whitifh, and very thin ; but at the angles they have 
a thicker afped, and on examining more ftridly, we find this thicknefs 
arifes from a Veffel in each of thofe Places. Thefe Veffels are conlider- 
ably larger than in either of the Rinds ; and we plainly enough difeern their 
cavities, when it is a new-cut piece that we examine. Thefe Veftels form 
the folid part of the Blea, and they are conneded and kept in their places 
by Membranes. They rife in diftind arrangements, fix in each ; and thefe 
make the fix angles of the feveral hexagonal Cells. Therefore the Blea 
is not compofed of various Couches of Veffels between two Membranes, 
as the inner Rind j but is one compleat and lingle fubftance, uniform in its 
flrudure ; and the whole of it is contained between two Membranes, which 
^re thin and pellucid. The Juice, which is abundant in thefe Veffels, 
continually 
