+Time Required for Cure.+ It is important to know when the patient may be allowed to walk about after an ulcer of the leg has been skin-grafted. If he begins too soon, the grafts will almost certainly become detached. That this will be so is evident from a consideration of the mode by which the adhesion of the grafts takes place. At first they adhere to the surface of the sore, simply by means of the effused and coagulated length. Cells rapidly spread into this length and in the course of two or three days the space between the grafts and the raw surfaces is occupied by a mass of young cells. In this tissue, new blood vessels develop and penetrate into the graft, whilst, at the same time, the cells of the latter grow and assist in the development of the young tissue and of the blood vessels. Thus the graft becomes vascularized; but for a considerable time the tissue between it and the surface of the sore contains many young blood vessels with delicate walls, and therefore, if the patient stands erect and allows the pressure of the column of blood to fall on these vessels, they rupture, and bleeding occurs beneath the graft and leads to its detachment. It requires a long time before the graft is firmly incorporated with the tissue beneath by the development of elastic fibres; indeed, it may be reckoned that this union is not complete until from three to six months have elapsed. The graft will, in all probability, be destroyed if the patient walks about within three months of the transplantation. Hence, unless that time can be devoted to the treatment, it is not worth employing skin-grafting for ulcer of the lower limbs. By this, however, it is not implied that it is necessary to keep the patient in bed for the entire time, but merely that the foot must not be allowed to hang down, nor must any weight be borne upon it. At the end of about six weeks the patient may be allowed to get up and lie on a sofa or sit with the leg on another chair, but the limb must not be permitted to hang down. After about three months he may be allowed to get about, but in order to prevent the detachment of the grafts, he should be fitted with a knee-rest and peg on which he walks, the leg projecting out behind him. If possible he should not put his foot to the ground until six months have elapsed. In cases of sores on other parts of the body, when the erect posture does not cause congestion of the part, the patient may be allowed to walk about after the first three weeks. +Results.+ The scar which results after skin-grafting performed in this manner is of a satisfactory character, and ulcers which have been intractable for years may be closed satisfactorily by this means. In order to obtain anything in the nature of a permanent cure, however, the prescribed period of rest must be adhered to rigidly. CHAPTER XX +LOCAL ANESTHESIA+