#The Skin.#—­The skin was the first tissue to be used for grafting purposes, and it is still employed with greater frequency than any other, as lesions causing defects of skin are extremely common and without the aid of grafts are tedious in healing.

Skin grafts may be applied to a raw surface or to one that is covered with granulations.

Skin grafting of raw surfaces is commonly indicated after operations for malignant disease in which considerable areas of skin must be sacrificed, and after accidents, such as avulsion of the scalp by machinery.

Skin grafting of granulating surfaces is chiefly employed to promote healing in the large defects of skin caused by severe burns; the grafting is carried out when the surface is covered by a uniform layer of healthy granulations and before the inevitable contraction of scar tissue makes itself manifest.  Before applying the grafts it is usual to scrape away the granulations until the young fibrous tissue underneath is exposed, but, if the granulations are healthy and can be rendered aseptic, the grafts may be placed on them directly.

If it is decided to scrape away the granulations, the oozing must be arrested by pressure with a pad of gauze, a sheet of dental rubber or green protective is placed next the raw surface to prevent the gauze adhering and starting the bleeding afresh when it is removed.

#Methods of Skin-Grafting.#—­Two methods are employed:  one in which the epidermis is mainly or exclusively employed—­epidermis or epithelial grafting; the other, in which the graft consists of the whole thickness of the true skin—­cutis-grafting.

Epidermis or Epithelial Grafting.—­The method introduced by the late Professor Thiersch of Leipsic is that almost universally practised.  It consists in transplanting strips of epidermis shaved from the surface of the skin, the razor passing through the tips of the papillae, which appear as tiny red points yielding a moderate ooze of blood.

The strips are obtained from the front and lateral aspects of the thigh or upper arm, the skin in those regions being pliable and comparatively free from hairs.

They are cut with a sharp hollow-ground razor or with Thiersch’s grafting knife, the blade of which is rinsed in alcohol and kept moistened with warm saline solution.  The cutting is made easier if the skin is well stretched and kept flat and perfectly steady, the operator’s left hand exerting traction on the skin behind, the hands of the assistant on the skin in front, one above and the other below the seat of operation.  To ensure uniform strips being cut, the razor is kept parallel with the surface and used with a short, rapid, sawing movement, so that, with a little practice, grafts six or eight inches long by one or two inches broad can readily be cut.  The patient is given a general anaesthetic, or regional anaesthesia is obtained by injections of a solution of one per cent. novocain into the line of the lateral and middle cutaneous nerves; the disinfection of the skin is carried out on the usual lines, any chemical agent being finally got rid of, however, by means of alcohol followed by saline solution.