On examining the affected parts after death or amputation, the tumor itself is found to consist of a soft substance, somewhat like the brain, of a greyish colour, and greasy appearance, with thin membranous-looking divisions running thro’ it, and cells, or abscesses, in different places, containing a thin bloody matter, occasionally in very considerable quantity. There does not seem uniformly to be any entire cyst surrounding the tumor, for it very frequently dives down betwixt the muscles, or down to the bone, to which it often appears to adhere. The neighbouring muscles are of a pale colour, and lose their fibrous appearance, becoming more like liver than muscle. The bones are uniformly caries, when in the vicinity of these tumors. If large, they are found rough, and broken off into fragments; if small, they are generally soft and porous. This tumor is sometimes caused by external violence; but often it appears without any evident cause. I know of no remedy which has a power of checking the progress of the complaint, or removing it. Friction, with anodyne balsams, sometimes gives relief in the early stages; but it does not seem to retard the progress of the disease. Extirpation is the only remedy which has a prospect of being successful; but it is only adviseable in the early stages, whilst the disease is entirely local, and has not extended to the neighbouring glands; for, after they become affected, the chance of recovery is greatly diminished. It is, however, sometimes difficult to persuade patients at this time to submit to amputation, or extirpation, because the pain and inconveniences are inconsiderable; but the operation ought to be urged with all the eagerness which a conviction of its absolute necessity, and its precarious issue, if delayed, will inspire. After making these observations, I shall illustrate the subject with the following cases, the first of which is intended to show the difficulty of extirpating the disease, when the operation is delayed after the first appearance of the tumor. In the second, we see the destruction which the bones suffer by it, and the extent of parts which it may affect. The third gives us an instance of the affection of the glands: And the fourth, of the most advanced stage, or that in which distant parts have suffered. The last is an instance of the good effects of an early operation. CASE I. William Stirling, without any very evident cause, perceived a small tumor on the top of the shoulder, about midway betwixt the termination of the neck and the articulation of the humerus. This gradually increased for some months, and by the time when I saw him was larger than a goose’s egg: It was spongy and elastic, and attended occasionally with pain.