To Make White Sauce for Fowls

Take a scrag of veal, the necks of fowls, or any bits of mutton or veal you have; put them in a sauce pan with a blade or two of mace, a few black pepper corns, one anchovy, a head of celery, a bunch of sweet herbs, a slice of the end of a lemon; put in a quart of water, cover it close, let it boil till it is reduced to half a pint, strain it, and thicken it with a quarter of a pound of butter mixed with flour, boil it five or six minutes, put in two spoonsful of pickled mushrooms, mix the yelks of two eggs with a tea cup full of good cream and a little nutmeg--put it in the sauce, keep shaking it over the fire, but don't let it boil.