Such an abscess may persist for years with no symptoms beyond a moderate enlargement of the shaft of the bone at the point of abscess, and the enlargement may be so slight that it is not recognized by the patient. In other cases the entire shaft may be enlarged, but the bone may not be tender. In most cases, however, such a localized abscess sooner or later gives rise to recurring attacks of pain, which, as a rule, are extremely violent. The intervals between such attacks may vary from days to weeks, or to months, or even to years. The attacks of pain may come on, apparently, perfectly spontaneously. Associated with these attacks of pain, the bone over the abscess usually is exceedingly tender to touch. With the attacks of pain may come a rise of temperature, or in some cases, there may be no disturbance of the general condition. This kind of abscess may be of small size, no larger than a pea, or may involve a great portion of the shaft of the bone; in such abscesses no definite sequestrum may ever form. The recognition of such conditions depends upon recurrent attacks of violent pain over circumscribed areas of bone, with or without constitutional disturbance, and nearly always with extreme local tenderness. +Treatment.+ In the acute stage there is suppuration of the marrow, more or less extended throughout the shaft, with often a subperiosteal abscess and perhaps abscess of the soft parts. The indications are the same as in any other acute suppuration; the pus must be evacuated and the bone cavity drained. This demands not only an incision into the soft parts, but an opening into the shaft of the bone. If a piece of necrotic bone is present, it should be removed. In the chronic stage there is usually an old necrotic shaft perforated by sinuses, and often freely movable, inclosed by a shell of dense periosteal bone. The sequestrum must be removed, but the bony defect fails to heal, and for months persists as a filthy, discharging cavity, with the constant danger of secondary infection and phlegmon, or erysipelatous inflammation. The healing of this cavity is very difficult and requires a very long time. Many methods have been tried for the filling of these bone cavities with blood clot, iodoform and oil of sesame, but they have not been successful, because it is almost impossible to render such cavities absolutely aseptic. +Tuberculosis of Bone.+ Tuberculosis of bone is always dependent upon infection of the marrow of bone by the tubercule bacillus. This germ obtains entrance to the bone marrow and causes the formation of miliary tubercules which arise from the proliferation of the connective tissue of the marrow around the primary tubercule. Other secondary tubercules are formed by extension of the tubercule bacillus. The centres of these tubercules become caseous, and, by fusion of adjacent caseous areas, also cause softening in the bone marrow.