70 
VEGETABLE STRUCTURE. 
terflice between that and the inner, is thus prefcrved. At the joining of 
tlie links there are a kind of knots: not at every joint, but at every third, 
fourth, or fifth, fo that in the whole they are very numerous. Thefe 
knots have their origin from an opening which is between the two ends of 
the two links j for they are fafiened to one another at the two edges only, 
and not throughout the whole part where they touch. From tiiis open- 
ing in the center of the joint rifes a fmall Cone ; at the top of which is a 
long and very narrow flit ; which is capable of being diflended or con- 
trafted, according to the ftate of the Plant. The inner Membrane is cut 
in the fame form at every one of thefe flits ; and the glandular fwelling 
round the aperture, alone preferves all the juices from being difcharged 
this way: this ferves the fame purpofe with the hairs in the other Plants j 
and in the fame manner unites the outer to the inner Rind. 
In the Hyacinth, the outer Bark is equally diflindt and colourlefs. The 
Veflels are flender, they are placed more diflant than in the Narciffus, and 
are joined to one another by crofs-bars, as in the Hellebore. The mouths 
by which they open into the interflicc of the two Barks, are glandular, 
and conic, as in the Narciffus ; but they are larger and fewer ; and they 
do not rife at the joints, but are the abfolute terminations of certain bran- 
ches of the Veffels. So that in this Plant, while the greater part of the 
Veflels purfue their uninterrupted courfc upwards, others terminate at dif- 
ferent heights, and in confiderable numbers, in abfolute glandular heads, 
difcharging their contents between the two barks, and fixing one to the 
other. Round each of thefe glands, as alfo round the others in the Narcif- 
fus, and in all the Plants of this kind, there is continually feen a kind of 
bladder of a peculiar Juice. This is the liquor difcharged from the Gland, 
which makes its way flowly at the minute openings of the inner Mem- 
brane ; and it is evident, that the Juices thus difcharged, have fuffered an 
alteration in the Glands, for they are thicker and more coloured than thofe 
in the Veflels. Often thefe Glands appear to rife from the Membranes 
themfelves ; but there is always a communication with the Veflels. 
In the outer Bark of the Stockjulyflower, the Veflels are large and 
branched j they run a lefs regular courfe than in any of the preceding ; 
but they are joined by crofs Veflels in the manner of bars, one to another, 
as all the refl. At many of thefe joints, but not at all of them, there aie 
round Ample fwellings ; perforated by very minute and naked holes, which 
open into the interftice between the two Rinds. 
In the outer Bark of the Pervinca the conflrudion is very like that of 
the Bark from the body of the Hellebore Root : the fubflance refembles a 
2 net 
