Pare well twelve mutton kidneys and cut them into slices. Put into a frying-pan, with one ounce of butter, a tablespoonful of salt, and a teaspoonful of pepper. Toss them well for six minutes. Add half a pint of Madeira wine sauce (No. 185), squeeze in the juice of half a lemon, add another small piece of fresh butter, toss well again without boiling, and serve.