Trim the veal scallops so that they are approximately all the same size. (Save trimmings for sauces.) Sprinkle a little salt and pepper on each slice of meat. Place 2 or more leaves of fresh or dried sage on each veal slice, or sprinkle about a scant 1/4 teaspoon ground sage on each. Cut prosciutto to the same size as veal slices. Top each veal slice with a prosciutto slice. Roll up and secure with toothpicks or tie with kitchen thread. Coat each veal roll lightly with flour, shaking off excess flour. Divide butter between 2 large frying pans; heat it without browning. Over medium heat, cook veal rolls about 5 minutes, or until golden brown on all sides. Reduce heat and add 1/2 cup marsala and 1/4 cup beef bouillon to each frying pan. Cover frying pans and cook for 5 to 10 minutes longer; cooking time depends on the size and thickness of the rolls. Shake the pans frequently to prevent sticking. If necessary, add a little more beef bouillon; there should be 1 to 2 tablespoons sauce for each veal bird. Transfer the cooked veal birds to a heated serving dish and spoon the sauce over them. Serve immediately and very hot with a tossed green salad. 6 servings.