While these old-time surgeons insisted on the necessity for treating all depressed fractures, and even suggested that many fissure fractures required trephining, they deprecated meddlesome surgery of the cranium, unless there was evident necessity, quite as much as we do now. Surgeons who in every serious wound of the head have recourse to the trephine must, they said, be looked upon as fools and idiots (_idioti et stolidi_). When operations were done on the head, cold particularly was to be avoided. The operations were not to be done in cold weather, and above all not in cold places. The air of the operating-room must be warmed artificially. Hot plates should surround the patient's head while the operation was being performed. If this were not possible they were to be done by candlelight, the candle being held as close as possible in a warm room. They had many experiences with fractures at the base of the skull. Hæmorrhages from the mouth and nose and from the ears were considered a bad sign. They even suggested, for diagnostic purposes, what seems to us the rather dangerous procedure that the patient should hold his mouth and nostrils tight shut and blow strongly. One of their methods of negative diagnosis for fractures of the skull was that, if the patient were able to bring his teeth together strongly, or to crack a nut without pain, then there was no fracture present. One of the commentators, however, adds to this, as well he might, _sed hoc aliquando fallit_--"but this sign sometimes fails." Split or crack fractures were also diagnosticated by the methods suggested by Hippocrates of pouring some coloured fluid over the skull after the bone was exposed, when a linear fracture would show by coloration. The Four Masters suggest a sort of red ink for this purpose.