i 1
rl
i f
E X P L A I N E D BY THE MICROSCOPE.
I f fome of thefe packets be worked about with geiitlenefs, the open ends will
give an opportunity of getting fome velTels feparate and fingle. Thefe being put
i n t o fpirit of turpentine, will, after a week's Handing, beeome very tranfparent : and
one of thenj, viewed with a great power, appears as at Fig. 4. divided in a very wond
e r f u l manner tranfverfely into cells i thefe are fliort, oval, and terminated by hollow
•valves; andufually, fome of them being full, and others empty, the conftruffion is
very pret t i l y fliewn. We fee at b I fome parts of thofe pin-hol e glands; and it is
fingular they always have their origin at the bafe of a cell longer than the others.
T h e brownnefs of the concreted juice in the Oak, from which all thefe obfervations
are taken, renders the cells which are filled very diffinguifliable : but there are other
veffels, with colours more diflingnifliable ftill, to be mentioned in the fucceeding
chapters.
P L A T E
X L
F i g . 4-
C H A P . IF,
OF THE VASA PROPRIA INTEEIORA.
» - p H E S E are Veffels generally of more importance than tlie preceding; and often
o f more than any other part of the Tree, They are in fuch kinds as are renowned
for medicinal virtues ufually large : they carry the mi l k juices in the Sumach;
and thegreateft quantity of the turpentine, as alfo the fineft and higheft Savoured, is
lodged in them, in all the kinds of Pine. Their fuuation is ffiewn in the Oak in
P l a t e IIL at let ter but tho' they are of no moderate fize in that Tree, they are
yet much larger in the Pines; we ihould therefore felef l a Tree of that genus for the
t r a c i n g them in the prefent inftance, if there were no other caufe of preference: but
•tis our bufinefs to fee them as clear and free f rom their juices as poffible, in order to
underftand their ftrudure; and happily the juice which fills them in the Pines, being
a pure turpentine, is capable of a per fefl folut ion in fpirit of wine.
- The fpecies of Pine i n which thefe Veffels are feen mof t of all diilinaly, is the Pinus
O r i e n t a l i s of the Botanical Writers. They are vaft apertures in every kind of Pine.
I f we view them juf t cut, we fee bubbles of a yellow turpentine rifing out of them.
I f a thin tranfverfe llice is laid before the Mlcrofcope, after foaking in fpirit of wine,
t h e y appear as great oval holes, into w h i d i draws might be thruft wi thout doing them
violence. Such afeffion of the Oriental Pine is given a tPlatcXl I . Fig. ,. where we
fee a chain of thefe vaft apertures regularly placed in the fubftance of the inner Rind,
and conforming themfelves to the ftape of the Branch. Fi g .
P L A T E xir.