Clean and pick over oysters as for Oyster Stew; reserve
liquor, add oysters slightly chopped, heat slowly to boiling-point,
and let simmer twenty minutes. Strain through
cheese-cloth, reheat liquor, and thicken with butter and flour
cooked together. Scald milk with onion, celery, mace, parsley,
and bay leaf; remove seasonings, and add to oyster
liquor. Season with salt and pepper.