1. In a heavy 3- to 4-quart casserole, combine the veal, chicken stock, water, salt and a few grin dings of pepper.
2. Bring to a boil over high heat, skimming off the scum and foam as they rise to the surface.
3. Reduce the heat to low, partially cover the casserole, and simmer for 30 minutes.
4. Stir in the carrots, celery and potatoes, and simmer partially covered for about 20 minutes longer, or until the meat is tender and the vegetables are soft but still intact.
5. Stir in the horseradish and vinegar, and taste for seasoning; if you have used prepared horseradish, add more vinegar to taste if you want.
6. Serve at once, directly from the casserole or from a heated bowl.
