1?
3 X P L A I N E D BY THE MICROSCOPE.
B O O K II .
O P THE VissELS OF TR E E S ,
C H A P . I.
OF THE VASA PROPKIA EXTERIORA : or. THE OUTER RANOE OF PECULIAR.
VESSELS IN TREES.
' T ^ H E Vafa propria, or peculiar Vcffels m Trees, are not of the nature or Condi- PLATE
"F conftituent parts, already defcribed. Thefe kit arc elTential to tlie XI.
nature of a Tree, as a Tree: the others are accidcntal, and belong only to the fpecies.
The Vegetable StruSnre can exift without thefe; but it cannot without the others.
They contain the particular juices on which the virtues, qualities, and fpecific properties
of Trees depend. A Tree can grow and live, and give fliade without them; but it
cannot have eminent qualities. Thofe are greateft where thefe Vafa propria are largeft
or moft numerous : and where we fcarce fee thefe, we hardly tafte or fmell the other.
Of thefe Veffels there are many ranges difpofed in or between the feveral parts •
their lituation could not be underftood from defcription, until thofe parts were particularly
known; but now they will be traced with eafe.
Of the Vafa propria there are four kinds; and of thefe each has its allotted plaee.
Its peculiar form, its di f t rent ftruflurc, and its feparate ufe. Some trees have them
m all their parts j others in fome of them; and there are which fliew them not at
all. Where they are not difcernible by the eye, reference is to be had to the tafte;
f o r i f there be nothing perceived by that, where none appear to the light, itm.y be
reafonable to give over the fcarch, and conclude there are none.
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