95 
VEGETABLE STRUCTURE. 
The moft extraordinary part of the Pith is that in the R^eptacle, ig. 
107, 107. Clofe under this, that is, at the head of the Flower Stalk, 
the FleOiy Subftance makes a fair arch, returning upon itfelf fo as to Itop 
and terminate the column of Pith within it there, 107, ^ From this 
part it fends up each way a portion of its upper furface, b b, winch makes 
the Cone of the Receptacle j and within this is form d a new Pith, with 
new Series of Vefiels. A portion of the Pith of the Receptacle is repre- 
fented feparately at 108. , r 1 
The fubftance of the Seed Veffels is formed of the Blea which this 
Flefliy Cone flioots out on the furface j and the Pith of the Cone begins 
and terminates in it. , r tt 11 
After examining, in this manner, the two Barks of the Flellebore, 
we continued the fame courfe of enquiry to the like parts of other 1 lants . 
and thefe appeared to be, in all effential articles, the lame with the firR. 
In the fame manner I have purfued the courfe and ftrudure of the Blea 
the Vafcular Series, the Pith, and the red, in feveral other Plants i and 
find that the generality have them all ; and none have any more : their 
place is the fame in all, and their courfe the fame, as alio is their ft«uau«:e. 
Therefore what we have feen here to be the compofition and confiruaion 
of the Hellebore, we have a right to believe is the Vegetable Stiuaure in 
general. If there be variations in fome kinds, they are flight; 'and the 
general fyflem is not affeaed by them, any more than the generical cha- 
raaers are by fpecific diftinaions. ^ . m 1 • 
It has been thought peculiar to the Pith, in certain Trees, that it oc- 
cupies a large fpace in their young Shoots, and flirinks fo as al molt to dil- 
appear, as the fame parts grow more confirmed in their conftruaion : but 
the prefent account of that part will, in fome degree, explain this wonder ; 
nor will the obfervation be applicable to the Pith alone. 
Young Shoots draw from the earth abundant moifture ; for out ot that 
is to be formed the Vegetable Syftem : but as a great deal is for this reafon 
taken into the Veffels of the Plant ; a great deal muft be alfo difcharged 
from them. This is done outwardly by the Hairs or downy matter coiu^- 
mon on young Stalks ; and inwardly, tho’ in a lefs degree by the Pith. 
This being the great ufe of thofe two parts, they are elTentia to the Plant 
in that ftate ; but they become unneceflary afterwards ; and therefore, in 
many Plants, and particularly in feveral Trees and. Shrubs, the young 
Shoots have a large Pith within, and a thick downy covering on the lur- 
face ; whereas, when they are grown harder, they become fmooth and 
folid. rr 
These 
