5. When the fistula does not get eaten through, having first examined it with a sound, cut down as far as it passes, and sprinkle with the flos aeris, and let it remain for five days. Then pour warm water upon it, and above lay flour mixed with water, and bind on it the leaves of beet. When the flos aeris comes away, and the fistulous sore becomes clean, cure it as before described. But if the fistula be in a part which does not admit of this treatment, and if it be deep, syringe it with the flowers of copper, and myrrh, and natron, diluted with urine, and introduce a piece of lead into the orifice of the fistula so that it may not close. Syringe the fistula by means of a quill attached to a bladder, so that the injection may distend the fistula. But it does not heal unless it be cut open.