It not unfrequently happens, that, after a sore which has been indolent has begun to heal, it, from fatigue, or some less evident cause, has a state of overaction induced, in which case, different appearances are exhibited, according to the previous state of the sore. If it has begun to form a natural cicatrix, this gives way, the surface becomes livid, the discharge thin, and the pain considerable. A thin slough of the granulations is then generally formed, and comes off in portions mixed with the discharge. If this state be not checked, it frequently comes to exhibit the acute symptoms of the overacting ulcer which was last described. More frequently, however, it occurs when the sore is still indolent, and not in the healing state, and when the edges still remain callous, and the granulations foul and unhealthy. If, at this time, a disproportionate, or overaction be induced, by exercise or otherwise, we find, that the surface becomes dark and sloughy, the granulations flat and indistinct, the discharge is increased, and the margins become tumid, and of a modena colour, whilst the surrounding integuments are of a dull red mottled colour, or erythematous; and the foot, if it take place in the leg, is frequently cold, and the pain darts down to the toe. This state is not unfrequently produced in old ulcers, by a disease of the parts below[60], which has been induced by the long continuance of the ulcer, which renders the bone carious, if it lie immediately under it (in which case, the first species of overacting ulcers is produced); but, at other times, by the sympathy of association, a diseased formative action (owing to the diseased formative action in the ulcer, or the imperfect granulations which are formed) is induced in the neighbouring parts, the muscles become pale, and have less of their fibrous texture, or the bone becomes rough, or pointed, like shagreen, and also becomes thickened, but without any appearance of caries. This diseased condition of the parts reacts on the ulcer, and induces overaction. [60] This affection of the ulcer, produced by a disease of the parts below, is induced with a frequency nearly proportioned to the aptitude of the part below for becoming diseased, by the continuance of an ulcer over them. Tendons and bones are particularly apt to be injured in this way; and, therefore, ulcers seated over tendinous parts, or bones thinly covered, are more apt to affect these, and to be reacted on themselves, than when seated over fleshy parts. On the same account, ulcers on the foot, or ankle joint, are worse to heal than those a little farther up the leg; and the difference is greater than can be explained wholly, by the circumstance of distance from the heart, and possessing less power of performing action properly. Recent ulcers likewise heal easily on the feet, by proper treatment. It is old ulcers alone which are difficult to manage, and the cause is obvious.