Osteoporosis Sometimes Arises From An Inflammation Of The Bone And Medulla, which furnishes a product in the cavities of the bone, differing in its nature from the ordinary ossific exudation (p. 129). This may be inferred from the traces of recent bony exudation, which are found on bones affected with osteoporosis, and from the fact of the bone beneath soft parts which are in a state of inflammation and ulceration, and that in the neighborhood of caries, being similarly rarefied (p. 133). Moreover, that very painful disease, the malum coxae senile (which, by the way, occurs in other joints also), appears to originate in a process of this kind: I hold it to be an inflammatory process of a gouty character, which gives rise to rarefaction, swelling, and a peculiar deformity of the head of the femur and acetabulum, - an osteoporosis succeeded by induration.

These cases of osteoporosis are curable.

r. A large class of osteoporosis is occasioned by atrophy of the bone. The enlargement of the Haversian canals and the cells, is, in such cases, the result of attenuation of the bony lamellae which form their walls. There is no increase in the volume of the bone, but rather a diminution: it shrinks and becomes smaller: the enlarged cavities of the bone are filled with a gelatinous or fatty substance, which is mostly of a dirty red, brown, or chocolate color. The long bones which have a very thick compact wall, are easily fractured; and spongy bones may be broken into by slight pressure with the finger (osteopsathyrosis). The bones have lost more or less of their weight, according to the degree which the disease has reached, and the patients themselves are specifically lighter than water (Saillant).

Senile Atrophy Of The Bones

Senile Atrophy Of The Bones, as it is the most common instance, may serve also as the type of this form of osteoporosis. But it occurs also in youth and manhood, and is then a painful disease, which usually extends over the whole 'skeleton, and which it is the custom to ascribe to gout, rheumatism, mercurial cachexia, syphiloid disease, and lepra. In the persons we have mentioned, it sometimes proceeds to such an extent, that in spongy bones considerable cavities are formed, which are filled with the diseased marrow above described; and it predisposes to the occurrence of fractures upon the slightest occasions. The part of the skeleton which suffers least in this form of the disease, is the skull. Like molli-ties ossium, it has proved up to the present time incurable.

b. There are two forms in which softening of bone presents itself, namely, rhachitis and mollities ossium. Some rarefaction is always present in both, but the essential part of the disease is a return of the bone towards its original cartilaginous structure; while at the same time it may be altered in its chemical composition or not. Hence the bones are not brittle, but soft and flexible; they become curved and misshapen, and are much more easily bent than broken.