Ibn Sina (Avicenna) was a great philosopher and physician. At the age of ten years he had completed the study of the Koran in Bukhara, where afterwards a certain Natili became his tutor, with whom he first studied the 'Eisagoge' of Porphyry, and afterwards Euclid, and lastly the 'Almagest' of Ptolemy. Natili then departed, and an ardent desire to study medicine having taken possession of Ibn Sina, he commenced to read medical books, which not being so difficult to understand as mathematics and metaphysics, he made such rapid progress in them that he soon became an excellent physician, and cured his patients by treating them with well-approved remedies. He began also to study jurisprudence before he was thirteen. At the age of eighteen he entered the service of a prince of the Beni Saman dynasty, Nuh bin Mansur, at Bukhara, a paralytic, who entertained many physicians at his court, and Ibn Sina joined their number. There he composed his 'Collection,' in which he treated of all the sciences except mathematics, and there also he wrote his book of 'The Acquirer and the Acquired.' He then left Bukhara, and lived in various towns of Khurasan, but never went further west, spending his whole life in the countries beyond the Oxus, in Khwarizm and in Persia, although he wrote in Arabic. It would be superfluous to follow all his changes of fortune, but it may be mentioned that when he was the first physician and vizier of Mezd-ud-daulah, a sultan of the Bowide dynasty, he was twice deposed and put in irons. He also appears to have acted treacherously towards Ala-ud-daulah, a prince of Ispahan, who was his benefactor. He was four years in prison, but at last succeeded in deceiving his guardians, and escaped. His dangerous travels, and the depression of mind inseparable from reverses of fortune, however, never interrupted his scientific pursuits. His taste for study and his activity were such that, as he himself informs us, not a single day passed in which he had not written fifty leaflets. The list of manuscripts left by him, and scattered in various libraries of Europe, is considerable, and though many of his works have been lost, some are still in existence. The fatigues of his long journeys, and the excesses of all kinds in which he indulged, abridged the life of this celebrated scholar, who died in A.D. 1037, at the age of fifty-six, at Hamadan, where the following epitaph adorns his tomb: 'The great philosopher, the great physician, Ibn Sina, is dead. His books on philosophy have not taught him the art of living well, nor his books on medicine the art of living long.'