Unfortunately, the pioneer work done by William and his great disciple did not have that effect upon succeeding generations which it should have had. There was a question in men's minds as to whether nature worked better by primary union or by means of the suppurative process. In the next century surgeons took the wrong horn of the dilemma and even so distinguished a surgeon as Guy de Chauliac, who has been called, not without good cause, the father of surgery, came to the conclusion that suppuration was practically a necessary process in the healing of large wounds at least, and that it must be encouraged rather than discouraged. This doctrine did not have its first set-back until the famous incident in Ambroise Paré's career, when one morning after a battle, coming to his patients expecting to find many of them very severely ill, he found them on the contrary in better condition than the others for whom he had no forebodings. In accord with old custom {86} he poured boiling oil into the wounds of all patients, but the great surgeon's supply of oil had failed the day before and he used plain water to cleanse the wounds of a number, fearing the worst for them, however, because of the poison that must necessarily stay in their wounds and then had the agreeable disappointment of finding these patients in much better condition than those whom he had treated with all the rules of his art, as they then were. Even this incident, however, did not serve to correct entirely the old idea as to the value of suppuration and down to Lister's time, that is almost the last quarter of the Nineteenth Century, there is still question of the value of suppuration in expediting the healing of wounds, and we hear of laudable pus and of the proper inflammatory reaction that is expected to bring about wound repair. The danger of wounds of the neck is, of course, not a modern doctrine, and yet very few people would think for a moment that it could be traced back to the middle of the Thirteenth Century and to a practical teacher of surgery in a medieval Italian university. Here once more there is evidence of the work of a careful observer who has seen patients expire in a few minutes as the result of some serious incident during the course of operations upon the neck. He did not realize that the danger was due, in many cases, to the sucking in of air into the large veins, but even at the present time this question is not wholly settled and the problem as to the danger of the presence of air is still the subject of investigation.