( iji > 
yill. An Account of a preternatural Bony Sub- 
fiance found in the Cavity of the Thorax, com- 
municated in a Letter to Vr, Rutty, by Mr* 
William GifFar4, Surgeon^ 
O N Tuejday, May the 172'^, I open’d the 
Body oi a Perfon, who dy’d the foregoing Day 
of a Peripueumoma ; in the right fide of whofe Thorax 
I found an oflcous Subftance about the fourth of an Inch 
thick, fix Inches long, and three broad, extending it felf 
underthe third, fourth, fifth and fixth Ribs, clofely and 
ftrongly conneded to the Perhfteum of the Ribs, and 
the Tunica propria of the inner Intarcoftal Mufcles, by 
Fibres which fliot from a ftrong and thick intervening 
Membrane, which clofely adher’d to its outer Surface 
or Back, and was continu’d over its inner likcwife, 
thereby forming a Capfula for this praeternatural Sub- 
llance. Its upper Edge lay immediately below, and 
was contiguous to that Part of the Ribs, where they be- 
come cartilaginous : The Membrane that adher’d to, 
and cover’d it, continu’d thick fome diftance from it, 
and gradually grew thinner, and was at length loft in 
the Pleura j from whence I judg’d this extraneous Body 
to have been form’d between the two Lamella of that 
Membrane. The Lungs fo ftrongly adher’d to its In- 
fide, that upon feparating them, part remain’d to it : 
Upon cutting into which, I obferv’d all the Cells 
Huff’d with a thin, but fomewhat digefted Pus. 
Upon farther Enquiry, I found on the fame fide, to- 
wards the Back, another Subftance, but perfectly Bone, 
invefted as the former, with a ftrong and thick Mem- 
brane 
