372 IMMUNOGENETICS 



concave (no. 12) Bard-Parker scalpel, pulling the scalpel against the firmest skin 

 attachment and curving the cut back up to create a circular graft about 1 cm. in 

 diameter and with even margins. About a dozen grafts can be taken from a single 

 donor, if he has been sacrificed. Each graft is then placed with its dermal side down- 

 ward on sterile filter paper, moistened with sterile physiological saline in a sterile petri 

 dish. Only the dorsal skin is used, but this can extend to the base of the tail and the 

 ears and along the sides of the animal. 



After the grafts are all in the petri dish, spread face downward, the donor is dis- 

 carded or placed aside to recover, and the grafts are one by one turned dermal side 

 upward and the panniculus carnosus is carefully scraped away with a dull, straight 

 scalpel. To do this, a pointed forceps is used to press down the graft at a point near its 

 margin, and the panniculus can be pulled loose in a single piece. Care must be taken 

 not to injure the underlying dermis, and the last evidences of fat should be scraped 

 away, leaving a thin, even graft. This is again turned dermal side down. 



The recipient mouse is anesthetized, and an area of his dorsal surface on the right 

 side in the chest region is clipped and disinfected with Zephiran solution. Use the 

 lower margin of the dorsal rib cage and the scapula as markers. It is convenient to 

 graft on the right side of the midline, reserving the left side for an autograft or a later 

 graft. 



Using a fine, sharp, curved scissors carefully pinch off an area of the skin and clip 

 it with the scissors. If this is done properly, the skin through the dermis will be 

 removed in a narrow slit, exposing the recipient's panniculus carnosus. This will be 

 evident by its glistening surface with intact blood vessels running through it. The 

 recipient area is then cleared by cutting away the skin with the scissors at the margins 

 until an area somewhat larger than the prospective graft is exposed. There should be 

 a margin of free surface (1 or 2 mm.) around the graft when it is in place. A selected 

 graft is then put in place, being careful that the dermal side is down, and it is then 

 covered with a piece of vaseline-impregnated, rather fine gauze, about \ inch by 

 | inch. The gauze should have been prepared in quantity and sterilized earlier. It 

 is convenient to sterilize the gauze in large rectangles and then to cut it as required in 

 the petri dish. All of these manipulations are with sterile forceps and scissors. Care 

 must be taken to cover the entire recipient surface with the gauze and not to disturb 

 the graft from this point forward. A piece of plaster-of-paris bandage (we use Gypsona) 

 about 7 inches in length and -f inch wide is moistened and the excess moisture shaken 

 free. These pieces have been rolled on small lengths of plastic tubing about an inch 

 long, secured with a small rubber band and stored in jars. There is no need to sterilize 

 them. The moist strip is first unrolled and placed over the graft area so that an inch 

 or more projects to the animal's right. The main roll is then passed under the animal's 

 body and returned to the right side ventrally, and the dorsal projecting strip is grasped 

 along its full width with a forceps. Tension is exerted on the lower strip while the 

 forceps holds the upper strip firmly in place so that it does not slide over the vaseline 

 gauze. After the first complete loop, the forceps is carefully released and pulled out 



