Vesalius' translation of Rhazes was probably undertaken because he recognized in him a kindred spirit of original investigation and inquiry, whose work, because it was many centuries old, would command the weight of an authority and at the same time help in the controversy over Galenic questions. This, of itself, would be quite enough to make the reputation of Rhazes, even if we did not know from the writings themselves and from the admiration of many distinguished men as well as the incentive that his works have so often proved to original observation, that he is an important link in the chain of observers in medicine, who, though we would naturally expect them to be so frequent, are really so rare. ALI ABBAS Rhazes lived well on into the tenth century. His successor in prestige, though not his serious rival, was Ali Ben el-Abbas, usually spoken of in medical literature as Ali Abbas, a distinguished Arabian physician who died near the end of the tenth century. He wrote a book on medicine which, because of its dedication to the Sultan, to whom he was body-physician, is known as the "Liber Regius," or "Royal Book of Medicine." This became the leading text-book of medicine for the Arabs until replaced by the "Canon of Avicenna" some two centuries later. The "Liber Regius" was an extremely practical work and, like most of the Arabian books of the early times, is simple and direct, quite without many of the objectionable features that developed later in Arabian medicine. It is valuable mainly for its contributions to diet and the fact that Ali Abbas tested many of his medicines on ailing animals before applying them to men. Of course, it owes much to earlier writers on medicine, and especially to Paul of AEgina. An example of its practical value is to be found in his description of the treatment of a wound of the brachial artery, when, as happened often in venesection from the median basilic vein, it was injured through carelessness or inadvertence. If astringent or cauterizing methods do not stop the bleeding, the artery should be exposed, carefully isolated, tied in two places above and below the wound, and then cut across between them. He has many similar practical bits of technique. For instance, in pulling a back tooth he recommends that the gums be incised so as to loosen them around the roots, and then the tooth itself may be drawn with a special forceps which he calls a molar forceps. In ascites he recommends that when other means fail an opening should be made three finger-breadths below the navel with a pointed phlebotomy knife, and a portion of the fluid allowed to evacuate itself. A tube should then be inserted, but closed. The next day more of the fluid should be allowed to come away, and then the tube removed and the abdomen wrapped with a firm bandage.