While at the University, I received an injury in one of my eyes, which deprived me of the sight of it. The other, soon after, was attacked by inflammation so severely, that, for some time, I lost the sight of that also; and though it was subsequently restored, the organ was so much disordered as to remain permanently debilitated, while twice in my life, since, I have been deprived of the use of it for all purposes of reading and writing, for several years together. It was during one of these periods that I received from Madrid the materials for the "History of Ferdinand and Isabella," and in my disabled condition, with my Transatlantic treasures lying around me, I was like one pining from hunger in the midst of abundance. In this state, I resolved to make the ear, if possible, do the work of the eye. I procured the services of a secretary, who read to me the various authorities; and in time I became so far familiar with the sounds of the different foreign languages (to some of which, indeed, I had been previously accustomed by a residence abroad), that I could comprehend his reading without much difficulty. As the reader proceeded, I dictated copious notes; and, when these had swelled to a considerable amount, they were read to me repeatedly, till I had mastered their contents sufficiently for the purposes of composition. The same notes furnished an easy means of reference to sustain the text. Still another difficulty occurred, in the mechanical labor of writing, which I found a severe trial to the eye. This was remedied by means of a writing-case, such as is used by the blind, which enabled me to commit my thoughts to paper without the aid of sight, serving me equally well in the dark as in the light. The characters thus formed made a near approach to hieroglyphics; but my secretary became expert in the art of deciphering, and a fair copy--with a liberal allowance for unavoidable blunders--was transcribed for the 'use of the printer. I have described the process with more minuteness, as some curiosity has been repeatedly expressed in reference to my modus operandi under my privations, and the knowledge of it may be of some assistance to others in similar circumstances.