Note 3 — PREFACE.

He was about five years old when he fell a victim to small-pox and almost lost his sight from it. But a weakness in his eyes continued to trouble him and he became, in middle age, I presume, totally blind.3 Some of his biographers would have us believe he was born blind; others state that he completely lost his sight when he was attacked by the virulent disease; and a few intimate that he could see slightly at least with the right eye. As to whether or not he was blind when he was sent to Halab to pursue his studies, his biographers do not agree. My theory, based on the careful perusal of his poems and on a statement advanced by one of his biographers,4 is that he lost his sight gradually, and total blindness must have come upon him either in his youth or his middle age.5 Were we to believe that he was born blind or that he suffered the complete loss of his sight in his boyhood, we should be at a loss to know, not how he wrote his books, for that was done by dictation; not how he taught his pupils, for that was done by lectures; but how he himself was taught in the absence in those days of a regular system of instruction for the blind.