Pagel, in Puschmann's "Handbook of the History of Medicine," declares that Rhazes' most important work for pure medicine is his monograph on smallpox. Its principal value is due to the fact that, though he has consulted old authorities carefully, his discussion of the disease is founded almost entirely on his own experience. His description of the various stages of the disease, of the forms of the eruption, and of the differential diagnosis, is very accurate. He compares the course of the fever with that of other fevers, and brings out exactly what constitutes the disease. His suggestions as to prognosis are excellent. Those cases, he declares, are particularly serious in which the eruption takes on a dark, or greenish, or violet color. The prognosis is also unfavorable for those cases which, having considerable fever, have only a slight amount of rash. His treatment of the disease in young persons was by venesection and cool douches. Cold water and acid drinks should be administered freely, so that sweat and other excretions may carry off poisonous materials. Care must be taken to watch the pulse, the breathing, the appearance of the feet, the evacuations from the bowels, and to modify therapy in accordance with these indications. The eruption is to be encouraged by external warmth and special care must be taken with regard to complications in the eyes, the ears, the nose, the mouth, and the pharynx. A fact that will, perhaps, give the best idea to modern readers of the place of Rhazes in the history of medicine is that Vesalius considered it worth his while to make a translation of his principal work. Unfortunately that translation has not come down to us. When Vesalius, pestered by the controversies that had come upon him because of his venturing to make his observations for himself, accepted the post of physician to the Emperor Charles V, he burnt a number of his manuscripts. Among these were his translation of Rhazes and some annotations on Galen, which, as he says himself, had grown into a huge volume. The Galenists were bitterly decrying his refusal to accept Galen on many points, and both of these works would have added fuel to the flame of controversy. He deemed it wiser, then, not to give any further opportunities for rancorous criticism, and, feeling presumably that in his new and important post it was not worth while to bother further over the matter, he burnt them. He tells the reason in his letters to Joachin Roelant: "When I was about to leave Italy to go to Court, since a number of the physicians whom you know had made the worst kind of censure of my books, both to the Emperor himself, and to other rulers, I burned all the manuscripts that were left, although I had never suffered a moment under the displeasure of the Emperor because of these complaints, and in spite of the fact that a number of friends who were present urged me not to destroy them."