Essence of Tame or Wild Ducks

This is made with the fragments of six roasted duck bones, broken up and put into a saucepan with one pint of mirepoix stock, one quart of veal blond (No. 423), a bunch of parsley garnished with bay leaf and thyme, mignonette and nutmeg. Let simmer for one hour, then add the juice of an orange and a lemon, also their peels; strain through a napkin or a silk sieve.