Brush chicken pieces with oil, saute until brown. Cover the bottom of a heavy 6-quart casserole with a mixture of the celery and sauteed onion, add the parsley and tarragon. Pour the vermouth over them, sprinkle with the salt, pepper, and a dash or two of nutmeg, Lay the chicken pieces on top. Sprinkle the garlic cloves around and between the chicken pieces. Cover the top of the casserole tightly with aluminum foil and then lid (this creates an airtight seal so the steam does not escape). Bake in a 375 preheated degrees oven for 11/2 hours, without removing the cover. Serve the chicken, pan juices, and whole garlic cloves with slices of heated French bread or hot toast. The garlic should be squeezed from the root end of its papery husk onto the bread or toast, spread like butter, and eaten with the chicken.