eri-articular fat and between muscles and tendons. It may be tough and
fibrous, or soft, vascular, and oedematous, and the peri-articular fat
becomes swollen and gelatinous, constituting a layer of considerable
thickness. The fat disappears and is replaced by a mucoid effusion
between the fibrous bundles of connective tissue. This is what was
formerly known as _gelatinous degeneration_ of the synovial membrane. In
the case of the wrist the newly formed connective tissue may fix the
tendons in their sheaths, interfering with the movements of the fingers.
In relation to the bones also there may be reactive changes, resulting
in the formation of spicules of new bone on the periosteal surfaces and
at the attachment of the capsular and other ligaments; these are only
met with where pyogenic infection has been superadded.

_Terminations and Sequelae._--A natural process of cure may occur at any
stage, the tuberculous tissue being replaced by scar tissue. Recovery is
apt to be attended with impairment of movement due to adhesions,
ankylosis, or contracture of the peri-articular structures. Caseous foci
in the interior of the bones may become encapsulated, and a cure be thus
effected, or they may be the cause of a relapse of the disease at a
later date. Interference with growth is comparatively common, and may
involve only the epiphysial junctions in the immediate vicinity of the
joint affected, or those of all the bones of the limb. This is well seen
in adults who have suffered from severe disease of the hip in
childhood--the entire limb, including the foot, being shorter and
smaller than the corresponding parts of the opposite side.

Atrophic conditions are also met with, the bones undergoing fatty
atrophy, so that in extreme cases they may be cut with a knife or be
easily fractured. These atrophic conditions are most marked in bedridden
patients, and are largely due to disuse of the limb; they are recovered
from if it is able to resume its functions.

#Clinical Features.#--These vary with the different anatomical forms of
the disease, and with the joint affected.

Sometimes the disease is ushered in by a febrile attack attended with
pains in several joints--described by John Duncan as _tuberculous
arthritic fever_. This is liable to be mistaken for rheumatic fever,
from which, however, it differs in that there is no real migration from
joint to joint; there is an absence of sweating and of cardiac
complications; and no be