VEGETABLE STRUCTURE. 
89 
Wherever a Fibre is to be produced, a portion of the furface of this 
Flefliy Subftance riles in a Bllfter, and forcing its way outward, takes the 
Coats with it. The courfe of the Flefliy Subftance itfelf is not altered 
by this } only a portion is raifed from it. Thus it is entire in itfelf j and 
thus all the parts of a Plant are produced by it. 
It is extremely difficult to know its flrudure, for the great quantity 
of matter in it renders it opake, Secftions cut tranfv’erfely ffiom a Fibre*, 
fhew it bed : ; but when the other parts are cleared away, the Vafcular 
Series, and Conic Cluflers, remain fixed firmly to it j itfelf appearing of a 
woody fubfiance. See Plate VI. Fig. 70, where a is the Flefiiy Subfiance, 
^ the Vafcular Series, which furrounds it, and c the Conic Clufters with- 
in. But in this view we difcover very little of its own texture. 
In fedllons cut from Fibres longer macerated, we fee that it is vafcular, 
as at Fig. 71 ; but it is not compofed wholly of VelTels, for there are Ribs 
of a folid Matter in the angles, which are form’d between them. We 
mufi: go further yet to fee It truly. A fedtion of a macerated Fibre mufi: 
be cleaned in fair water, hardened in alum-water, and then plunged in 
fpirit of wine ; in this it is to remain a week, and we ffiall then have it 
in a condition fit to be viewed. 
The VelTels of which this Flefhy Subftance is compofed, may then be 
eafily feen in a thin tranfverfe fedion laid before the Double Microfcope, 
as at Fig. 72 j and we fee plainly why all was obfcure before. The Vef- 
fels of this part do not contain a watery or colourlefs liquor, as thofe of 
the others; but the elTential Juice of the Plant : whereon depend its tafte, 
fmell, and virtues. All thefe are, in a manner, centered in this, and in 
thofe procefi.es of it which run in amongfi: the Blea ; thefe ufually break 
off in feparatingthis fubftance from the reft ; therefore they are not figured 
here. This Juice is thick, and coloured, and fo flowly leaves the VelTels, 
even in the thinnefi: fedlons, that the tops of them continue covered 
over, and the interftices as well as their cavities filled with it; fo that all 
appears one opake mafs. 
When a foft water has penetrated this Juice, and a folution of alum 
hardened the coats of the VelTels which contain it, fpirit of wine, with- 
out affeding them, will, in a great meafure, difiblve, and abforb it; then 
the VelTels, appear diftindly, as in Fig. 72. They are round, they have 
large cavities, their Coats are fupported by woody Fibres, and clufters of 
the like Fibres run up in all the fpaces which thofe round bodies leave 
in touching one another. Thefe are larger than in the other parts of the 
VoL. I. N Plant; 
