VEGETABLE STRUCTURE. 
69 
The Pulfatilla, which comes next in this gradation, fiiews that thefe 
bars are not of abfolute necefTity to the ufe of this part ; for in its outer 
Bark there are none. The VefTels are large 5 they are placed much nearer 
to one another than in the Hellebore ; and they have no communication 
one with the other. I have traced a fingle Veflel from the bottom to tlie 
top of the Stalk, and found it no way, nor no where, joined to the reft. 
Thefe Vedels have their opening inward, as in other outer Barks 5 but it is in 
a manner very different from the former. The juices they convey are thicker 
and more coloured than in the generality of other Plants j and there are 
at various didances in all the VefTels a kind of Glands, at which they flop : 
thefe are darker than the reft of the Veftel, and fomewhat fvvelled ; and 
lengthwife of each fwelled part, there is opened a fmall flit, which has no 
fringe or hairynefs about it. This flit pierces the inner membrane, and 
can difeharge its liquor into the fpace between this Rind and that next un- 
der it. 
The Stalk of the Pulfatilla is extremely hairy; thefe hairs are white 
tubes, rifing immediately from the furface of the VefTels, and opening with 
a plain mouth into them. 
In the Polyanthous Primrofe, the VefTels are difpofed exadlly as in the 
Hellebore Barks, only the bars are fmaller, and the openings are by round 
fringed mouths along the furface of the afeending VefTels. The Bark of 
this Primrofe comes off very freely, but it is difficult to get the outer one 
pure. The colour of the Stalk is owing to the inner Rind ; for the outer 
Bark is perfectly colourlefs : this will flievv whether the two come off to- 
gether, for we never fee the outer Bark alone, unlefs it be very thin and 
perfedtly colourlefs. 
The outer Bark of the Narciflus affords a much more pleafing appear- 
ance : it is thin, perfedlly colourlefs, and very diftindl in the conftruddon. 
The VefTels icuthis are very fmall, and the fluid they contain is entirely 
watery ; they are made into a kind of links, joining by the ends, and be- 
ing thus united: in pairs, there are alfo crofs-bars, as in the other Barks, 
but not between the two VefTels of the fame pair ; thefe are joined only 
by the ends of the links : the crofs-bars go from the outfldes of each of 
thefe VefTels, to the outfldes of the VefTels of the next link. 
We trace the courfe and form of the VefTels in this Bark very happily; 
for there are no apertures either in their furfaces or in the crofs-bars ; no 
fringe of hairs to difturb the view, nor coloured juices, irregularly lodged, 
to intercept it. The whole conftrudlion is p'ain ; and that communication. 
Nature always makes between the VefTels of the outer Bark and the in- 
teiftica 
