1. Put into a 2 1/2-quart kettle tripe (ask butcher for parboiled variety), carcass of a roast chicken, a knuckle of veal or a beef shin bone and 8 cups of water. Bring to a boil, and skim off the foam. Cover and simmer 3 hours.
2. Heat butter, saute the pepper and onion in it.
3. Add to meat stock with the tomatoes and potato. Cover and cook 30 minutes longer. Remove the bones. Let cool. Add salt and pepper, skim off grease, heat again and serve.