VEGETABLE STRUCTURE, 
U9 
as there Is reciprocal rife and fall, it may affedl all the changes in the Plant, 
which the favourers of a Circulation have fuppofed to be proofs of that 
motion. This the philofophy of Dr. Hales ehabliflied, and all experi- 
ments prove it. But there is fomething more. 
The inner furface of the Vefiels of the Bark is covered with Glands: 
thefe fecrete a fomewhat richer part from the common watery Juice, dur- 
ing thefe its motions: and they difcharge it, thro’ apertures in the Mem- 
brane, into that fmall cavity which there is between the outer and inner 
Rinds. Thus while a great deal is received, and again evaporated, feme 
part is feparated and detained. To know what becomes of this, we mufl 
recoiled; the hrudure of the Inner Rind of Plants. 
This inner Rind of the Fibres of Roots abforbs alfo from the earth ; 
for the outer Bark is too thin and too fpungy to prevent the paflage of the 
moiilure. The VelTels of this inner Rind open by many mouths into the 
fpace between it and the outer, and there receive that part of the Juice of 
the Veflels in the outer Bark, which had been fecreted and difeharged thro’ 
their Glands. The nourilliment therefore received by the Veflels of the 
inner Rind from the earth and air, becomes enriched by this fecretion ; 
and in the fame manner its Glands, after a fecend elaboration, deliver it 
to the VelTels of the Blea. 
The Blea is compofed of Cells, which receive molllure from the earth 
and air, as do the VelTels of the two Rinds j and from this alfo a part is 
concoded by the Glands of thofe VelTels, and received into them. The 
Blea afeends to the furface of the earth, terminating in a kind of fhell 
over the Bud, as the inner Rind terminates in Rudiments of fucceeding 
Leaves. Both thefe parts go over the thin body of the Root ; and in the 
Vellels of both there is the fame afeending motion of the Juices in the day, 
and defeent at night : but there appears in the conflrudion of the Blea a 
manifeft and elTential difference from theirs. 
The watery nourilhment, and this fecreted richer fluid, flow together 
in the VelTels of the inner Rind 3 but in the Blea it is otherwife. The 
cells of the Blea hold the watery Juice j and its Veflels contain only this 
fecreted fluid, which is, by thefe various operations, become high Colour- 
ed, thick, and of fome tafte and fmell. 
This rich Juice from the VelTels of the Blea is difeharged thro’ VelTels, 
W'hich pierce the Membrane of the Vafcular Series, into the Shell, a, which 
is the Flelli of the Plant : nor does that part of the Plant receive nourilli- 
ment any other way. 
T 2 
Thus 
