In the chapter on the medieval care of the insane, there are some clinical observations and suggestions as to treatment from Paul which make it very clear what a careful observer he was, and how rational in his application of such knowledge as he had to the treatment of patients. Probably his contributions to the difficult subject psychiatry, well above a thousand years ago, will serve to make his genius as a physician clearer than almost anything else that could be said of him. Among the great Arabian physicians who represent the transition period, from the earlier Middle Ages directly under Greek influence, still surviving to the later Middle Ages, when the earlier Renaissance brought back the Greek masters once more, were Rhazes, Ali Abbas, Avicenna--whose name had been transformed from the Arabic Ibn Sina--Abulcasis, Avenzoar, and Averroes, the last named a philosophic theorist but not a physician. The first three named were born in the East, the last three in Spain. Besides these Maimonides, the great Jewish physician, who was born and educated at Cordova in Spain, deserves a place. In this earlier period Rhazes must be mentioned, while the others who merit special attention will be considered in the chapter on Later Medieval Medicine. Rhazes (died 932) is one of the great epoch-makers in the history of medicine. He was the first to give us a clear description of smallpox. Some of his medical aphorisms are well worth noting, and make it very clear that he was a careful observer. "When you can heal by diet, prescribe no other remedy; and where simple remedies suffice, do not take complicated ones." Rhazes knew well the value of the influence of mind over body even in serious organic disease, and even though death seemed impending. One of his aphorisms is: "Physicians ought to console their patients even if the signs of impending death seem to be present." He considered the most valuable thing for the physician to do was to increase the patient's natural vitality. Hence his advice: "In treating a patient, let your first thought be to strengthen his natural vitality. If you strengthen that, you remove ever so many ills without more ado. If you weaken it, however, by the remedies that you use, you always work harm." The simpler the means by which the patient's cure can be brought about, the better in his opinion. He insists again and again on diet rather than artificial remedies. "It is good for the physician that he should be able to cure disease by means of diet, if possible, rather than by means of medicine." Another of his aphorisms seems worth while quoting: "The patient who consults a great many physicians is likely to have a very confused state of mind."