Cut the kidney in thin slices, and fry them with butter in a sautapan over a quick fire, season with chopped mushrooms, parsley and shalot, pepper and salt; shake in a . tablespoonful of flour; add a little Harvey sauce, lemon-juice, and a gill of stock or water; stir over the fire until the whole has simmered together for five minutes, and dish up with sippets of dry toast all round the dish.