seat of the disease, but frequently extends to those articulated with it. The soft parts are commonly more or less thickened, and rendered exceedingly dense by effusion of lymph into the cellular texture; and so great is this thickening sometimes, that the knife is resisted as if by cartilage. The discharge which proceeds from the carious part is generally highly fetid, very profuse, is often poured through several openings, and the surrounding skin is excoriated and generally of a livid colour. The ichorous discharge occasionally dries up for a short period and again breaks out more violently. The surface of the ulcer is, in some cases, occupied by soft unhealthy granulations; in others the earthy part of the bone is most prominent. When the parts have been macerated and dried, the disease is often found to have proceeded more in width than in depth, and the absorption has not reduced all points of the diseased surface to the same level, thin portions remaining somewhat elevated, and giving the part a cancellated appearance; and there often project numerous minute osseous fibrillæ of considerable length, which intermix with one another, and form a most delicate network. In other instances, the ulceration has extended more deeply and uniformly, and a considerable cavity is formed, with irregular margins and surface; not unfrequently it contains dead portions of the cancellated structure, in some of a dark, in others of a light colour; or it is occupied, in the recent state, by a substance resembling lard. The surrounding bone is much softened, and, after maceration, becomes exceedingly light. The disease is generally confined to one or two bones, but occasionally involves a whole chain. It may be limited to a part of one bone in a joint, or may embrace the whole of it. Its extent will depend on the severity of the primary action, or on the degree and duration of the pressure of fluid which has been allowed to exist, whether from the nature of the superincumbent texture or the carelessness of the surgeon. Interstitial absorption of those bones which are in the neighbourhood of the carious ulceration often occurs in the tarsus and carpus. The superincumbent integuments are livid and cold, and pain is felt in the situation of the bones; yet they are not affected with continuous ulceration, but portions of their substance are gradually removed by absorption, so that they are much loosened in texture, and may be altogether destroyed, or come to consist merely of a thin and reticulated osseous shell, whilst at the same time their cartilaginous surfaces often remain in their healthy condition.