Make a bouquet garni by wrapping parsley, thyme, rosemary, bay leaves, and peppercorns in a piece of cheesecloth. Tie with kitchen twine and set aside. Arrange meat, veal bones, onion, carrots and celery in an even layer in a heavy roasting pan. Roast, turning every 20 minutes, until the vegetables and the bones are deep brown, about 1 1/2 hours.