ng is usually maintained even in the presence of great
deformity. In a case observed by Byrom Bramwell, the patient suffered
from a succession of fractures over a period of years.

[Illustration: FIG. 135.--Cadaver, illustrating the alterations in the
Lower Limbs resulting from Ostitis Deformans.]

The disease may last for an indefinite period, the general health
remaining long unaffected. In a considerable number of the recorded
cases one of the bones became the seat of sarcoma.

#Osteomyelitis Fibrosa.#--This comparatively rare disease, which was
first described by Recklinghausen, presents many interesting features.
Because of its causing deformities of the bones and an undue liability
to fracture, and being chiefly met with in adolescents, it is regarded
by some authors as a juvenile form of Paget's disease. It may be
diffused throughout the skeleton--we have seen it in the skull and in
the bones of the extremities--or it may be confined to a single bone,
usually the femur, or, what is more remarkable, the condition may affect
a portion only of the shaft of a long bone and be sharply defined from
the normal bone in contact with it.

[Illustration: FIG. 136.--Osteomyelitis Fibrosa affecting Femora in a
man aet. 19. The curving of the bones is due to multiple fractures.]

On longitudinal section of a long bone during the active stage of the
disease, the marrow is seen to be replaced by a vascular young
connective tissue which encroaches on the surrounding spongy bone,
reducing it to the slenderest proportions; the formation of bone from
the periosteum does not keep pace with the absorption and replacement
going on in the interior, and the cortex may be reduced to a thin shell
of imperfectly calcified bone which can be cut with a knife. The young
connective tissue which replaces the marrow is not unlike that seen in
osteomalacia; it is highly vascular and may show haemorrhages of various
date; there are abundant giant cells of the myeloma type, and
degeneration and liquefaction of tissue may result in the formation of
cysts, which, when they constitute a prominent feature, are responsible
for the name--_osteomyelitis fibrosa cystica_--sometimes applied to the
condition.

It would appear that most of the recorded cases of _cysts of bone_ owe
their origin to this disease, while the abundance of giant cells with
occasional islands of cartilage in the wall of such cysts is responsible
for the view formerly held that t