the Caliph Nuhh with such brilliant success that his fame was established. In the course of a varied life he was at one time a Vizier, and soon afterwards in prison for being concerned in some sedition. He escaped from prison and lived for a long time concealed in the house of a friendly apothecary, where he wrote a large part of his voluminous "Canon." He spent the later years of his life at Ispahan, where he was in great favour with the Caliph Ola-Oddaula, and he died at Hamdan in 1038 in the fifty-eighth year of his age. He had led an irregular life, and it was said of him that all his philosophy failed to make him moral, and all his knowledge of medicine left him unable to take care of his own health.
Competent critics who have studied the medical teaching of Avicenna have not been able to discover wherein its merits have justified the high esteem to which it attained. The explanation appears to be that what Avicenna lacked in originality he made up in method. The main body of his "Canon" is a judicious selection from the Greek and Latin physicians, and from Rhazes and other of his Arabic predecessors. He wrote a great deal on drugs and remedies, but it has been found impossible to identify many of the substances of his Materia Medica, as in many cases the names he gives evidently do not apply to those given by Serapion, Rhazes, and other writers. He often prescribed camphor, and alluded to several different kinds; a solution of manna was a favourite medicine with him; he regarded corrosive sublimate as the most deadly of all poisons, but used it externally; iron he had three names for, probably different compounds; he had great faith in gold, silver, and precious stones; it was probably he who introduced the silvering and gilding of pills, but
