Sea.VL 
BussjE Mucosa of the Human B6dy. 
S E C T. VI. 
* 
General Observations on the Structure of th ^ 
Burs.^. 
■ Having confidered the lhape, fize, fituation, and connedion of the burfe 
•mucofe, we lhall now more particularly attend to their ftrudure. 
The proper membrane of the burfa is thin and tranfparent, but very denfe 
and capable of confining air or any other fluid. 
• • • * 
i V 
It is joined to the neighbouring parts by the common cellular fubflance. 
Between the burfa and the hard fubflance of bone a thin layer of cartilage or 
of tough membrane is very generally interpofed. 
To the cellular fubflance on the outfide of the burfa j the adipofe fubflance 
is conneded; except where the burfa covers a tendon, cartilage, or bone much 
expofed to preflTure and fridion. 
• 
In feveral places a mafs of fat, eovered with the continuation of the mem- 
brane of the burfa, projeds into its cavity: And, in all fuch places, the mem- 
brane covering the fatty fubflance has a red colour, from the number of blood- 
veflTels which run on its outer fide, or between it and the fat; and from the 
edges and extremities of the fatty fubflances fringes projed (r). 
The inner fide of the membrane of the burfa is not only fmooth, but, by 
the copious fecretion of a lubricating liqUor, is rendered extremely flippery. 
SECT. VII. 
' (r) i'feTab.L X.— Tab. III. d. Tab. IV. M.— Tab.V. u. Tab. VI. F. Tab. VIII. 
fig. i 6 , 17- 
