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In viewing the afcending Veffels in Oak, I found 
fome other VelTels, which enter’d into their fides, 
and appear’d to me like fo many fmall round holes, 
efpecially where the Horizontal Veflels lay, which 
I judged to be united to the afcending VelTels, by 
means of thofe fmall Orifices, and thereby to dif- 
charge part of their Sap into them. 
Taking a fmall Twig of an Oak, which in feven 
Years growth was grown to about the thicknefs of 
ones Finger, I cut it thro’ according to the length 
both of the afcending and horizontal VelTels, which 
Iaft I faw lying in great Numbers very clofe toge- 
ther, and proceeding direttly from the Pith of the 
Twig. 
I have likewife made fome Obfervations upon Fir 
Wood, in which the afcending VelTels confifl of fo 
very fine and thin a Subfiance, that they exhibit a 
very delightful Spe&acle in the Microfcope. In thefe 
afcending VelTels I imagin’d that 1 faw fome Globules, 
with a fmall opening in their middle, which feem’d 
to be of a clofer and denfer Subfiance than the reft 
of the Wood. But I afterwards found myfelf mifla- 
ken, and that thefe fuppofed Globules were nothing 
elfe but the Orifices, whereby the afcending and ho- 
rizontal VelTels were united together, and through 
which the Sap was carry ’d from the one to the 
other. 
From thefe Obfervations I turn’d my Thoughts to 
the flefhy Fibres of Animals, and began to confider 
with my felf, that, fince the Author of Nature ufu- 
ally obferves the fame Frame and Structure in a 
great variety of his Creatures, perhaps the fine 
Membranes, with which every Mufcular Fibre is 
invefled, and which are provided with an innume- 
rable 
