The advantage of this method is that the epidermal layers can be collected at random from various patients who present themselves with blistered surfaces—the result of burns—or where the skin has been raised by some blistering process for counterirritative reasons.
This loose skin is collected and spread upon a glass plate and sterilized in warm boric-acid solution, then allowed to dry in this position to prevent curling, and, when dry, cut into desirable sizes and laid away for future use.
d. Heterodermic Skin-grafting.—In this mode of skin-grafting the pieces of skin are taken from freshly amputated limbs of one patient or from any selected part of the body of the newly dead, and placed upon the defects to be covered in another patient. These grafts have been successfully employed even after ninety-six hours had elapsed between the time of amputation or the death of a person and the taking of the skin-grafts.
The method employed is as follows: The site of the amputated member or dead body from which the skin is to be taken is thoroughly cleansed, as in the Thiersch method. Pieces of the skin, including the subcutaneous tissue, but no fat, are cut from the cleansed parts. These sections are cut into smaller pieces, about one inch square (Hartman and Weirick), and placed upon the granulating surface to be covered, leaving one-half-inch wide interval between each piece.
The grafts are then covered with overlapping narrow strips of rubber tissue, over which a normal saline dressing is applied. The outer dressing is composed of gauze saturated with the same solution. These dressings are changed every twenty-four hours.
The grafts will soon be found to adhere, showing a pinkish color in about six days; those showing a tendency to undergo gangrene or a laziness of attachment at this time are removed.
In about two weeks the epitheliar surfaces of these grafts are thrown off, as with other grafts already mentioned, and shortly thereafter a new, deep-pink epithelium is formed, the ends of the grafts throw out epitheliar cells, which soon coalesce with those of the neighboring grafts, eventually taking on the normal appearance and vitality of skin.
3. Zoödermic Skin-grafting
The advantage of using zoödermic grafts is that the patient is saved the ordeal of general anesthesia and the secondary wound occasioned by the removal of the graft, which necessarily leaves more or less of a scar.