In a greased baking dish with vegetable oil put fat and heated to melting. Add the crushed bones, cut into pieces of meat and other ingredients (without chervil leaves, parsley and spices). Bake in moderate oven (170-180 C), stirring them occasionally and scatter with a little water until bone gain a nice brown color. Sprinkle with powdered sugar, then it is caramelized, moved into a deep dish and pour 2 liters of cold water. Then boil the liquid eliminates foam generated. Add chopped parsley and chervil, pepper, salt and bay leaf. All boil over low heat for about 3 hours. The broth is harvested fat and it is strained through a sieve, then put in the refrigerator to precipitate and freeze the remaining fat. Fat is harvested, and the broth is heated a little, strain through moistened gauze in hot water and pour into clean small bottles. In the neck of each bottle is placed in a pinch salicyl (crushed aspirin) and 1 teaspoon melted tallow. The bottles are closed tightly with a pre-scoured plugs and kept cool. The contents of the bottle after opening it should be used quickly.