Carefully raise and turn back the skin of a small leg of mutton, being careful not to tear it. Then lard the joint all over with fine strips of celery previously half cooked in a little stock, strips of cucumbers, a few branches of tarragon, and some strips of fat bacon. Cover the whole rather thickly with a mixture of minced anchovies and minced herbs, with pepper and salt. Now replace the skin and carefully sew it to the joint so as to cover over the larded surface. Roast the whole on a spit before an open fire and serve with its gravy.