Three writers whom we have already mentioned (Early Medieval Medicine)--Aëtius, Alexander of Tralles, and Paul of Ægina--were, as we have seen, all of them interested in surgery, and wrote very interestingly on that subject. It is, however, from the end of the Middle Ages--that is, from the writers of the twelfth century down to the end of the fifteenth--that surprising contributions were made to surgical knowledge. This surgery of the end of the Middle Ages began its development at Salerno. The first great textbook was that of Roger--known also as Rogero and Ruggiero, with the adjective Parmensis or Salernitanus, of Parma or Salerno--who wrote his work about 1180. It is of this that Gurlt, in his "History of Surgery," vol. i., p. 701, says: "Though Arabian works on surgery had been brought over to Italy by Constantine Africanus a hundred years before Roger's time, these exercised no influence over Italian surgery in the next century, and there is scarcely a trace of the surgical knowledge of the Arabs to be found in Roger's works." He insisted, further, that Arabisms are not found in Roger's writings, while many Græcisms occur. The Salernitan School of Surgery drank, then, at the fountain-head of Greek surgery. After Roger comes Rolando, his pupil, who wrote a commentary on his master's work, and then the combined work of both of them was subsequently annotated by the Four Masters. It is this textbook, the work of many hands and the combined experience of many great teachers, that is the foundation stone of modern surgery. Some of the expressions in this volume will serve to give the best idea of how thoroughly these surgeons of the later medieval period studied their cases, how careful they were in observation, and how well they solved many problems that we are inclined to think of as having come up for serious consideration only much later than this time. After studying their chapter on Injuries of the Head, it is easy to understand why Gurlt should declare that, though there is some doubt about the names of the authors, this volume makes it very clear that these writers drew their opinions from a rich experience. They warn about the possibility of fracture of the skull even when there is no penetrating wound of the scalp, and they even suggest the advisability of exploratory incision when there is some good reason for suspicion of, though no evident sign of, fracture. In "Old-Time Makers of Medicine," I quoted some of the details of this teaching as to head surgery that may serve to illustrate what these surgeons taught on this important subject.