Book II. of Trunks. 129 
C HAP. IL 
Of the Structure of the Parts. 
THIRD enquiry, is into the Generation and 
Strudfure of Parts. The manner whereof I have 
already endeavoured to explicate (. T from the A- (4) Lib. 2. 
natomy of the Root, throughout all particulars. P. 2. 
Some whereof I fhall yet further clear. 
1. $. . As Firft, the Union of the Barque to the 
a> Er Body ofthe Tree, Contrary to the common Opie 
nion, That they are not continuous; but that the Bargue only furrounds 
the Body, asa Scabbard does a Sword, or a Glove the Hand. As alfo 
feemeth to be proved, by the eafy slipping of the Barque of Willow, 
and moft other Trees, when full of Sap, from the Wood, 
2. $. But, notwithftanding this, they are as truly continuous, as 
the Skin of the Body is with the Flefh : fê. by meansof the Parenchy- 
ma , which is one entire Body, running from the Bargue into the Wood, _ , 
and fo uniting both together; as ina Branch of Vine or Corin-Tree, Tab. 19. 
when the Barque is {tripped off, is apparent 5 the Spaces between the 
de they ar feveral Parts of the Wood, being filled up with the Parenchymous, infer- 
fides; ai ted from the Barque. 
either me 3. $. Now the reafon why the Bargue neverthelef flips fo eafily 
ith the fai from the Wood, is plain, viz. Becaufe moft of the young Veffels and Pa- 
none fiè renchymons Parts, are there every year fucceflively formed 5 that is, be- 
y all whit twixt the Wood and Barque : where the faid Parts newly formed, are 
into the b as tender, as the tendereft Vefels in Animals. And we may imagine, 
how eafie it were at once to tear or break a thoufand vefeéls or Fibres 
Ur, the bi of an Embrio, of a Womb or Egg. . 
cial 4 $ THE fame Veffels of the Barque being always braced, and 
ie on radually falling off, together with the Parenchyma, into the utmoft 
Ssg Rira + Hence it is, that the Bargues of many Trees, are asit were, lat- Tab. 19: 
lake ticed with feveral Cracks of divers Sizesand fometimes in the Figure of 
wits Rombe: the fid Fifires reprefenting the Foftion and Trait of the 
Veffels in their Braces. Hence alfo it is, that the Barque of fome Trees, 
as of Corin, Cherry, Exc. falleth off in Rings, fe. becaufe the Sap-Veffels 
are pofited in the fame manner in the Barque. 
5. $. The Sap-Veffels, as they are generated at the inner Verge of 
the Barque : fo likewife, in a fmall quantity, at the utmoft Verge of the 
Ae Pith. Thefe being not only fed with a more vigorous Sap, but with 
depot b reat caution, fecured within the Wood, for the propagation of the 
erin S ucceeding Buds. 
, sop Fife 6. $. Hence alfo it is, that is, by the annual accretion of thefe 
Veffels that the Pith is fometimes leß in the Truwk, than in the Branches5 Tab, 18, 
and leß in the elder Branches, than in the youuger; and fometimes ‘tis 
allmoft wholly filled up. By which means, as the Branches carry every 
year a greater burthen 5 fothey become (till more fturdy the better to 
füpport it. 
= 7. § SOMETIMES alfothe Pith breaks and fhrinks up, thus 
making the Truzk a Pipe, The caufe whereof, is either the Largenef 
of its Pores, or the Thinnefs ofthe sides of the faid Pores; upon both 
zZ which 
