Prepare a bouillon from 3 lbs beef, 1 lb veal, and root vegetables. Strain the bouillon. Fillet 20 ruff,* wash the bones, and add the bones to the bouillon with ¼ lb rice, 10 field mushrooms, and 1 spoon butter. Pour on a little bouillon, boil until soft, and rub through a sieve. Dilute with the remaining bouillon, set the pan of soup in a saucepan of boiling water, and stir as often as possible to prevent the purée from settling. Skin the fish, cook the fillets in bouillon, and transfer them to the soup tureen. Mix 2 egg yolks and ½ glass thick cream, strain, and dilute with 1 glass of soup. Place on top of the stove and heat, stirring, until very hot. Dilute with the rest of the soup and garnish with parsley and dill.