Cover rabbit pieces with cold salted water in a saucepan (2 to 3 tablespoons salt to 6 to 8 cups water).
Let stand about 1 hour.
Drain off the water in saucepan and add the broth, carrot, celery, and onion to rabbit.
Bring to boiling; reduce heat and cook slowly, covered, 1 hour.
Strain the liquid and return to saucepan with the rabbit.
Add tomato sauce and Worcestershire sauce and continue cooking slowly about 30 minutes, or until rabbit is tender.
Remove rabbit to heated serving dish.
Combine 2 to 3 tablespoons flour with 1/4 cup cold water and stir into the cooking liquid; cook and stir until boiling and thickened.
Season to taste with salt and pepper and cook several minutes longer.
Pour over the rabbit or serve in a bowl.