becomes diffusely thickened and infiltrated with granulation tissue
which eats into and replaces the articular cartilage. Clinically, the
condition resembles tuberculous disease of the synovial membrane, for
which it is probably frequently mistaken, but in the syphilitic
affection the swelling is nodular and uneven, and the subjective
symptoms are slight, mobility is little impaired, and yet the deformity
is considerable.

_Syphilitic osteo-arthritis_ results from a gumma in the periosteum or
marrow of one of the adjacent bones. There is gradual enlargement of one
of the bones, the patient complains of pains, which are worst at night.
The disease may extend to the synovial membrane and be attended with
effusion into the joint, or it may erupt on the periosteal surface and
invade the skin, forming one or more sinuses. The further progress is
complicated by the occurrence of pyogenic infection leading to necrosis
of bone, in the knee-joint, for example, the patella or one of the
condyles of the femur or tibia, may furnish a sequestrum. In such cases,
anti-syphilitic treatment must be supplemented by operation for the
removal of the diseased tissues. In the knee, excision is rarely
necessary; but in the elbow it may be called for to obtain a movable
joint.

In #inherited syphilis# the earliest joint affections are those in which
there is an effusion into the joint, especially the knee or elbow; and
in exceptional cases pyogenic infection may be superadded, and pus form
in the joint.

In older children, a gummatous synovitis is met with of which the most
striking features are: its insidious development, its chronic course,
symmetrical distribution, freedom from pain, the free mobility of the
joint, its tendency to relapse, and its association with other
syphilitic stigmata, especially in the eyes. The knees are the joints
most frequently affected, and the condition usually yields readily to
anti-syphilitic treatment without impairment of function.

JOINT DISEASES ACCOMPANYING CERTAIN CONSTITUTIONAL CONDITIONS

#Gout.#--_Arthritis Urica._--One of the manifestations of gout is that
certain joints are liable to attacks of inflammation associated with the
deposit of a chalk-like material composed of sodium biurate, chiefly in
the matrix of the articular cartilage, it may be in streaks or patches
towards the central area of the joint, or throughout the entire extent
of the cartilage, which appears as if it had been pain