Take a sharp knife and score the skin across in narrow stripes (you may cross it again so as to form diamonds) and rub in some powdered sage. Raise the skin at the knuckle, and put in a stuffing of minced onion and sage, bread-crumbs, pepper, salt, and beaten yolk of egg. Fasten it down with a buttered string, or with skewers. You may make deep incisions in the meat of the large end of the leg, and stuff them also; pressing in the filling very hard. Rub a little sweet oil all over the skin with a brush or a goose-feather, to make it crisp and of a handsome brown. Do not place the spit too near the fire, lest the skin should burn and blister. A leg of pork will require from three to four hours to roast. Moisten it all the time by brushing it with sweet oil, or with fresh butter tied in a rag. To baste it with its own dripping will make the skin tough and hard. Skim the fat carefully from the gravy, which should be thickened with a little flour.