Saute chicken livers in butter 5 minutes or until brown. Remove livers, and drain on paper towels, reserving drippings in skillet. Saute mushrooms and onion in drippings until onion is golden. Stir in flour and salt. Add tomatoes, wine, parsley, and Worcestershire sauce; bring to a boil. Reduce heat and cook 5 minutes, stirring often. Add chicken livers; simmer 5 additional minutes. Serve over rice.