c $m > 
then the Spirits by their rotatory motion will determine 
forae of it to thofe little holes 5 fo that if any of thofe 
preternatural Foramina reach to the Superficies of the 
Bone, fome part of the nutritious Juice will be thrown 
out upon the furface of the Bone, where indurating into 
a bony fubftance it produces gummatous inequalities. 
The third Difcourfe concerns the Marrow, which has 
blood Veflels, both Veins and Arteries. The Organs by 
which the Medullary Oil is feparated, are final! Veficles 
or Glandules, which are conglomerated into diftind Lo- 
bules conteined in feveral Membranes or Baggs, which lie 
eonteined in one common Membrane inverting the 
whole Marrow : all which both Veficles, Baggs and Mem- 
brane are propagated from the exteriour Coat of the Ar- 
teries. The paflage of the Medullary Oil from all parts 
of the Marrow to the Bone is not by Dufts, but by 
Pores formed in the Veficles, by which it paffes from 
one to another, till it arrives at the fides or extreme 
parts of the Bone, 
The Medullary Oil, which is fupplyed to the Inter- 
faces of the Joynts, pafTesinto them by pa ffages pene- 
trating through the Bone into thefe Cavities, and formed 
for this end. 
The ufe of the Medullary Oil is either common to all 
the Bones,or more proper to the Joynts. To all the Bones 
it is ferviceable, and neceflary to preferve their temper* 
and keep them from being brittle. In the Articulations, 
Firft, It lubricates the extremities of the Bones, and fo 
makes them more apt to be moved. Secondly ,It preferves 
the ends of the articulated Bones from an inordinate in- 
calefcence. Thirdly, It prevents the Attrition of thofe 
parts of the Bones, which are rubbed one againft another. 
It is likewife beneficial to the Ligaments of the Joynts 
in preferving them from drynefs and rigidity, and lubri- 
cating thofe parts of them, which Aide upon the Bone. 
Thofe Cartilages alfo which are pyn'd to any of the 
Bones it preferves flexible. In 
