As to their Situation, they are differently seated in the several
Joints; in some they stand over-against the very Interstice of the
Bones, and run in a little way between them, where the Ends of the
Bones towards that Side are not contiguous, but so formed as in their
Conjunction to make an Interstice, and these are commonly in the
Manner of a Fringe; some are seated in some Sinus or Cavity, others
planted upon the Membrane, which immediately covers the Articulation:
In general they are so seated, that they cannot be injured by a
Compression from the Bones; and yet there is this Contrivance, that
the Bone does, either in the Inflexion or Extension of the Joint,
lightly press upon them, so as to promote the Excretion of the Humour,
which they separate into the Joints, when they are moved and stand
most in need of it; and by this Means it seems to be most plentifully
supplied, when there is occasion for the greatest Quantity of it, and
to be proportioned to the present Exigence, according to the State of
Rest, or the several Degrees of Motion in the Part when it is moved.
And it is no small Security to these Glands, against the Obstructions
which the mucilaginous Quality of the Liquor that they separate does
naturally dispose them to, that they are solicited, and the Liquor
expressed out of them by the Motion of the Parts where they are seated:
The same sort of Glands are placed about the common Membrane of the
Muscles, and about the Tendons.