Desault ordering extension to be again discontinued, recommenced the motions of the os femoris, and even increased their force, changing them in every direction, for the purpose of lacerating the capsule. After this, extension was again renewed, with better success than before. Indeed, on the very first effort, the head resumed, of itself, its natural situation, without any further assistance on the part of the surgeon. The sufferings of the patient ceased almost instantaneously; towards evening a slight swelling appeared around the joint, over which an emollient cataplasm was applied. On the day following, all the unfavourable symptoms were gone, and in about a fortnight the patient was able to return to his usual exercises, which, however, he was directed to pursue, for some time, with moderation. 2. There are, in this case, two circumstances, on which the practitioner should fix his attention, and which may throw great light on the reduction of all luxations of the os femoris, as they will be found applicable to most accidents of the kind. These are, 1st, The narrowness of the opening in the capsule. 2dly, The inutility of the motion or process of conformation, when that opening has been enlarged. 3. We formerly observed, when treating of luxations of the humerus, that one of the obstacles to reduction was, the narrowness of the opening in the capsule; the same circumstance occurs here. That membrane, lacerated at the time when the head of the os femoris is driven against it, is dilated sufficiently to let the head escape: but, the edges of the lacerated membrane, coming together again, and being thus drawn tight around the neck of the bone, retain it in that position, and prevent the head from re-entering the acetabulum. Thus, in a fracture, where one of the extremities of the bone is protruded through the integuments, the opening in the skin, by closing tightly round that extremity, sometimes prevents its reduction.