Sheaths may be opened surgically by means of a knife, and the removal of a portion of the wall of distended and atonic tendon sheaths is possible. These operations belong to the realm of surgery and are not properly a part of this treatise. However, in passing, it may be said that if a perfect technic is possible in doing the last named operation, a permanent recovery is the outcome. Fracture of the Metacarpus. Etiology and Occurrence.--As the result of all sorts of violence, such as falls and injuries in accidents of various kinds wherein the metacarpals are subjected to contusions, fractures may result. In the horse it is unusual for fracture of one of the small metacarpal bones to take place without there being at the same time a fracture of the third (large) metacarpal bone. Classification.--Fractures of the metacarpal bones as they occur, are as likely to be compound as simple, and the multiple and comminuted varieties are occasionally observed. The manner in which the third (large) metacarpus is fractured, largely determines the outcome in any given case. Symptomatology.--Abnormal mobility of the broken parts of bone and crepitation mark fracture of the metacarpus, and the condition is easily diagnosed. In many instances, when compound fracture exists, broken ends of bone are protruding through the skin. No weight is borne upon the fractured member ordinarily, although during the excitement occasioned by runaways, horses are sometimes seen to support weight with a broken leg even when the protruding bone is sunk into the ground in so doing. Prognosis.--Generally speaking, fractures other than the simple-transverse in young animals, are considered unfavorable cases. With the metacarpus, however, there are instances where compound fracture occurs in colts that justify treatment. But in all cases of compound fracture, the element of infection in addition to the increased difficulty in maintaining immobility of the broken bone, creates almost insuperable difficulties in the average instance. And unless the practitioner distinctly explains to his client the various reasons which make treatment an economic impracticability, dissatisfaction is likely to follow if treatment is instituted without such an understanding.