[ 206 3 
occafioncd by the nutritive Juice in the inner 
Cavity of the Bone., where the Medulla was wafted 
by an Ulcer, running out thro' feveral Holes made 
by it dire&ly into this joint. Fig . 2. reprefents the 
Exfoliation, which lay concealed within this Bone, 
until the Time the Operation above-mentioned, it 
was taken out by, was performed. This exfoliated 
Bone being harder than the main Bone itfelf it was 
inclofed in, and fecmingly found, whilft the latter 
was carious : Notwithstanding the caft-off Bone 
had been foaking longeft in the Matter extravafated 
and pent up in the medullary Cavity, which was 
the Original of the Spina ventofa , this Exfoliation, 
which was the firft Confequence of the extrava- 
fated Matter within, the Bone having, as it were, 
been detached from the main Bone, which was 
difiolved by it, fome time before it could poflibly 
reach the Body of the Bone itfelf. 
Fig . 1 . The Os Humeri amputated near the Shoulder- 
Joint b 7 with the two Bones of the Fore-Arm 
fa wed off in E F. a a a. a, Several large Openings 
in the Bone below and under the Deltoid Mufcle, 
where the Bone had formerly been diftemper’d and 
affe&ed by the Spina <ventofa 5 this Part of the 
Bone appearing found, and feemingly reftored to 
its natural State ; whilft all the reft of it down- 
wards is ftrangely alter’d by the Humour occa- 
floning it, and degenerating, as it were, into a 
cartilaginous Subftance, or fuch a one as coufd 
readily be cut with a Knife ; the interior being 
deftroyed by a Caiiofity, and the exterior, which, 
was fpread out beyond its natural Dimenfions, in- 
crufted by a callous Expanfion flicking to it, made 
folid. 
