E X P L A I N E D BY T H E MICROSCOPE.
C H A P . 11.
P A R T I C U L A R I T I E S IN THE VASA PROPRIA INTERIORAÍ
I . T H E I R S INGLE D I S T R I B U T I O N AND SMALL NUMBER
I N THE LARIX.
O
F thefc important Veflels, ( impor tant i n tlieir ufe to nian, tho' as i t flióuld fcem lefs P L A T É
fo than many other parts to the growt h of the Tree,) wc fee a great variety, in ^^XVl.
humber, difpofition, and contents : but in all, whatever may be their difference o f fize,
t h e i r ftru£ture is the fame. To underftand them beft, the way is to fee them where
t h e y are fimpleft and moft diftinft. The common Larch Tree is here feledted for
t h a t purpofe. In the fedlion of it, Plate XXXVI . wc fee, in the great fubftance of
i t s Bark, b, the mouths of a few VelTels; few, but very large, very confpicuouily ^
d i f t i n i t , and ferving in this light, to that moft ufeful purpofe, the clearing up a
doubt, which fome w h o have gone thro' thefe obfervations with me had entertained,
t i l l this objeft cleared them. The vaftnefs of thefe VelTels had rendered them fufpedled
not to be fuch, till I ihewed turpentine exailly filling and ouzing up from
t h e m , on cutting in fome kinds of Pine: and in others their fituation without the
centers of diftina cones of the Wood, confounded them in the imagination with thofe
iprotrufioQS of the parietes which are, as has been iliewn, the beginnings of eHcreafe
i n that part. But here alfo the Larix afforded a diftinft anfwer to the doubt. The '
W o o d of this Tree, tho' extreme' y delicate, d, is not formed into large cones at all, d
but difpofed between the feveral radii only : yet here appear thefe vail openings, c, as c
i n other cafes j and they are filled with a very fingular kind of liquid maftick.
iFor the reft, the Larix affords a very pleaiing and inftruitive view. The Rind is
thicker than in moft T r e e s ; and clofe within its verge, between that and the Bark,
are lodged the Vafa exteriora, d, in long and llcnder clufters, which at the laft-men- d
tionsd feafon may diftinguifli themfelves eminently by the juices they contain, they
being of a high crimfon. The Corona, e, is very beautiful i n the Lar ix; and its P i th, e
f , is clear. f
I I . O F T H E I R CLOS E DISPOSITION
I N T H E T A N A C E T U M F R U T I C A N S.
T h e number of thefe Veffels may be much greater, tho' in a fingle feries, than we PLATE
have feen them in the Larix. The Tanacetum Fruticans, a feftion of which is given XXXVII.
a t Plate XXXVI L is an inftance of this difpofition. In this fingular Shrub, which fo far
approaches
[ L
I.