VEGETABLE STRUCTURE. 
i9 
new, nothing muft be regarded but plain obfervation. It will be necelTary 
to the underftanding Vegetation, to trace thefe conic Clufters very care- 
fully, for their office is important, nor was it poffible the Growth and Life 
of Plants could be underftood while thefe remained unknown. 
Transverse fedlions of the parts ffiew the place and difpofition of thefe 
clufters, but ’tis in the fplit Roots we muft trace their origin. To this 
purpofe chufe a found Root of Hellebore j fplit this perpendicularly down, 
and chufing a part for obfervation that has a Fibre growing from it, cut 
away the reft : then fplit this piece again, fo that the knife may pafs thro’ 
the middle of the Fibre, and fplit that alfo down fome part of its length, 
cutting off the one half by a perpendicular ftroke. Such a piece of the 
Hellebore Root is reprefented Plate III. Fig. 33. and it is the only kind 
of fedion in which we can trace, in one view, the courfe of thefe clufters 
of Veffels in the Fibre, and in the body of the Root, fo as to fee what 
connedion there is between thefe conftituent parts, in diftind portions of the 
Plant. Such a fedion is reprefented Plate III. Fig. 33. The different 
faces in this figure all ftiew diftindly the feveral conftituent parts of the 
Plant ; and we fee at Letter a, in what manner the fame parts, namely the 
conic Clufters, and Vafcular Series, are diftinguiflied in a tranfverfe fec- 
'tion, which at b are fcarce to be difccvered in the longitudinal divifion, be- 
caufe they appear there only as a kind of Fibres running the fame courfe with 
the reft of the parts. 
We ftaall find, in tracing the courfe of the other parts in the purfuit of 
this fubjed, that the Fleffi of the Plant does not run entire from the body 
of the Root into the Fibres ; but the principal part of it purfuing a plain 
courfe round the Root, a portion only is fent off from its furface to form 
the Flefti of the Fibre. Therefore, in the body of the Root there is an 
hollow for holding the Pith, c c c \ and in the body of the Fibre there is 
• another, d d d. Thefe two hollows we fee do not open one into the other ; 
for this fedion is made thro’ the very center of the Fibre j and all that 
thicknefs of the Fleffi of the Plant reprefented 2X e e e, has its place be- 
tween them, nor is penetrated by any hollow whatfoever. Now the place 
of the conic Clufters of Veffcls is always within the Flefti of the Plant, 
as appears in all the tranfverfe fedions of this Plate. Therefore the mafs 
of impervious Flefli marked e e e, being between the clufters of the Fibres 
and thofe of the Root, they cannot be abfolute continuations the one of 
the other, any more than the Pith of the Fibre and the Pith of the Root. 
Their fituation is as diftind as their number. 
I 2 
What 
