C 3 4 o ) 
The third fort of Tuhuii are fcewn by Letter ///, 
and there I found not only placed in Circles orderly, but 
likewife in a different manner, as the large Veflels are 
in Wood, 
The fourth fort of Tubes large, incomparifon of the 
reft, are reprcfented by K K. LM are feveral cracks 
or clefts in the Bone caufed by the Preflure of the Knife, 
efpecially if it be not very fiiarp. 
Befides the above-mentioned four forts of Tubes run- 
"nirg the length-ways of the Bone, I (onetimes imagined 
I faw fome ifl a contrary Situation, which itemed to pro- 
ceed from the middle of: the Bone, and terminate at the 
circumference; and that the(e were of two fizes, where- 
of the fmalier were fuch as the above-mentioned lead 
fort, that for the mod part make up the length of the 
Bone. The Reafbn why I could not well dilcover the.e, 
'was, from their being at a great diftance from each o- 
* ther ; and fbme feemed as if perforated by thofe that 
run the length- ways. And though I could not be cer- 
v tain I faw thefe radiated Tuhuii, yet I do not qutftion 
their being there ; and I fuppofe the Teriofleum is moftly 
conftituted and nouriftied by thefe; the rather, fince we 
fee the fame in Trees, whofe Bark is formed by the 
tranfverfe fibres that run from the Center paffing be- 
tween the dire£t ones. And as we cannot determin the 
beginning of the Bark in the Tree, becaufeit is annually 
iornred anew out of all the Horizontal Veflefa ; fb I con- 
ceive that the Membranes furrounding the Bones have 
their encreafe from fbme Veffels proceeding from the 
-cavity of the Bone to the circumference, where they 
'are dilated into that thin foft Skin defending the Bone 
zs the Bark does the Tree. 
I know many believe the Origine and Nouriflbment of 
the Bark is from the Root ; but if it were fo, we fhould 
: lind the parts of the Bark near the Root larger, and rs- 
^mWyid into fmalier and fmalier as they run higher, as 
the 
