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The Anatomy Ban 
B.1.c.7. 
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tinued, are ufually wroaved without breaking 5 thofe fmaller ones 
by which they are flitched or woven together, eafily tear in fander 
all the way. 
31. And becaufe the Fibres of the Woof, are themfelves alfo of 
different Bulk; therefore it is, That where they are more fturdy, 
as ufually in the Root, they require a greater quantity of Warp, 
that is, a broader Plate, to overmatch them, Whereas, where they 
are more extream fimall, as in the Truk and Leaves, one Thred of the 
Warp, that is, one Spiral Fibre, will be ftrong enough of it felf, and 
fo, fometimes, be fingly #zroav'd. 
32. $. From the extream Tenuity of thefe Fibres, it is, That 
they are very rarely difcern'd, and not without the greateft difficulty. 
As alfo, from their great Tendernef 5 whereby not enduring to be 
drawn out,they all break off clofe to the Sides of the spiral ones. In the 
Pith, the like Tranfverfe Fibres are alittle more vifible: which firft 
conduéted Me to the notice of them here alfo. 
33. 9. All the Fibres of the Aer-Veffels, both the Warp and the 
Woof, are of the fame Subftantial Nature with the Pith and the other 
Parenchymous Parts of a Plant. From whence it is, That whereas the 
Towy Parts of a Plant, whereof all Linen Manufaitures are made, 
are very Strong and Tough thefe, as is abovefaid, are extream Tender 
and Brittle, like thofe of the Pith and all the Pithy Parts. To which 
therefore, the Aer-Veféls are tobe referrd. And the Content of both, 
is oftentimes the fame. 
34. $. From whence, we have a further proof of what I have 
formerly afferted 4 which is, That in all Plants, there are Two Sub- 
ftantially different Parts, and no more than Tio, viz. the Pithy, and 
the Tomy or Lignous Parts. 
35. §. From hence alfo we have fome ground tg conjecture, That 
fo many of the Aer-Veffls, at leaft, which are noe ane with the 
feed, but poff-zate, are originated from the Parenchymous Parts 5 which 
feem by fome alteration in the Quality, Pofition and Texture of the 
Fibres, to be Transformed into Aer-Vefels,as Caterpillars are into Flies. 
And as the Pith it felf, by the Rupture and Shrinking up of feveral 
Rows of Bladders, doth oftentimes become Tubulary: So is it alfo 
probable, that in the other Parenchymous Parts, one fingle Row or File 
of Bladders evenly and perpendicularly piled ; may fometimes, by the 
fhrinking up of their Horizontal Fibres, all regularly breakone into 
another and fo make one continnedCavity 5 or a Tube,whofe Diametre is 
the fame with that of the Bladders, wherof it is compofed. All which, 
will appear more probable, and what hath been faid, be yet better 
underftood, when we come, in the next Chapter, to the Defcription 
of the Pith, 
CHAE 
