These old surgeons must have had many experiences with fractures at the base of the skull. Hemorrhages from the mouth and nose, for instance, and from the ears were considered bad signs. They were inclined to suggest that openings into the skull should be discovered by efforts to demonstrate a connection between the mouth and nares and the brain cavity. For instance, in their commentary the Four Masters said: "Let the patient hold his mouth and nostrils tight shut and blow strongly." If there was any lessening of the pressure or any appearance of air in the wound in the scalp, then a connection between the mouth and nose was diagnosticated. This is ingenious but eminently dangerous because of the infectious material contained in the nasal and oral cavities, so likely to be forced by such pressure into the skull. They were particularly anxious to detect linear fractures. 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 "_sed hoc aliquando fallit_--but this sign sometimes fails." Split or crack fractures were also diagnosticated by the method suggested by Hippocrates of pouring some colored fluid over the skull after the bone was exposed, when the linear fracture would show by coloration. The Four Masters suggest a sort of red ink for this purpose. While they have so much to say about fractures of the skull and insist, over and over again, that though all depressed fractures need treatment and many fissure fractures require trepanation, still great care must be exercised in the selection of cases. They say, for instance, that surgeons who in every serious wound of the head have recourse to the trephine must be looked upon as "fools and idiots" (_idioti et stolidi_). In the light of what we now know about the necessity for absolute cleanliness,--asepsis as we have come to call it,--it is rather startling to note the directions that are given to a surgeon to be observed on the day when he is to do a trepanation. For obvious reasons I prefer to quote it in the Latin: "_Et nota quod die ilia cavendum est medico a coitu et malis cibis aera corrumpentibus, ut sunt allia, cepe, et hujusmodi, et colloquio mulieris menstruosae, et manus ejus debent esse mundae, etc._" My quotation is from Gurlt, Vol. I, p. 707. The directions are most interesting. The surgeon's hands must be clean, he must avoid the taking of food that may corrupt the air, such as onions, leeks, and the like; must avoid menstruating and other women, and in general must keep himself in a state of absolute cleanliness.