Fish Soup a la Ponsardin

Cut one pound of fillet of bass into slices a quarter of an inch thick, and one inch and a quarter in diameter; fry these in some butter, and set them under a weight; when cold pare them. Take the tails from one pound of shrimps, peel them, and keep the meat aside. Put into a saucepan, one very fresh bass head, also the parings cut from the fillets and the shrimps, add half a pound of stalks or parings of mushrooms, a quarter of a bottleful of white wine, and three quarts of water, also a bunch of parsley, thyme, bay leaf, carrots and minced onions; boil for thirty minutes, then strain. Make a blond roux with quarter of a pound of butter, and quarter of a pound of flour; moisten it with the fish broth, boil, despumate, and thicken it with egg-yolks, cream and lobster butter, with Kari; serve as a garnishing the shrimp tails and the small prepared fillets of bass.