CARIES most frequently occurs in the heads of long and in the cancellated structure of the short bones, as unhealthy suppuration most frequently takes place in the loose, fatty, and cellular tissues of the soft parts. The formation of abscess in the cancelli is generally preceded by deposit of tubercular matter, isolated or collected in masses, and by the softening of this cheesy substance. When pus has formed in the substance of a bone, the outer lamella, in the end, becomes absorbed, and the effusion undermines the periosteum, which, from the distension, also ulcerates: the matter then spreads into the neighbouring cellular tissue, or makes its way to the surface, and is evacuated, or, what is still worse, it escapes into an articulation. The discharge is often continued, as already stated, in consequence of a dead portion of the cancellated structure being imbedded either in the carious cavity, or in the soft parts, where they sometimes are lodged for a long period. [Illustration] It was formerly remarked that bones become highly sensible from incited action; hence, during the progress of this disease, which is attended with more or less inflammation, the patient generally suffers most excruciating agony—so great, in general, as to prevent him, perhaps for weeks, from enjoying the least repose. The affected part is considerably swollen, but the enlargement is seldom so general, or so great as in the diseased state of the ligaments and other apparatus of a joint. White swelling, however, may be the precursor of caries; or, in other words, a disease commencing in the bursæ, ligaments, synovial membrane, or cartilage, may extend to the bone; and breach of continuity, attended with weak action, be the consequence. In caries the affected portion appears neither to possess vitality enough to enable it to repair the breach, nor to be sufficiently deprived of vitality to be thrown off by the surrounding parts. Considerable portions of dead bone are occasionally found in carious cavities, in the heads of bones, and even in the vertebral column. Small portions are also detached piecemeal in the progress of ulceration, and discharged; but it is seldom that the whole surface is thrown off, so as to give place to a healthy and reparative action. When the parietes of the cavity have remained a considerable time in this inactive state, the surrounding vessels become more active, and the surface of the bone in the vicinity is studded with nodules of new osseous matter. The disease here delineated affected only a small portion of the cancellated texture of the condyle. An ashy looking substance fills the cavity, and this again was concealed in the recent state by lardaceous matter. The elbow joint is unaffected, excepting only that, from the deposit of new bone in spiculæ and nodules, and the condensation of the soft parts, almost complete anchylosis had taken place. This deposit is not always limited to the affected bone, if one only be the