That the inspirations of genius are really nothing more than spontaneous upsurgings from the depths of the subconscious, is indeed demonstrable from the recorded statements of men of genius themselves. To the modern psychologist one of the most impressive proofs of the actuality of subconscious mental processes, is the occasional solution in dreams of problems that have long baffled the waking consciousness. In this way abstruse mathematical problems have sometimes been worked out after all hope of solving them had been abandoned; and troublesome clerical errors, the perpetual dread of book-keepers, have been cleared away during sleep, as in the following typical instance, reported by a successful business man to the Society for Psychical Research: “I had been bothered since September with an error in my cash account for that month, and, despite many hours’ examination, it defied all my efforts, and I had almost given it up as a hopeless case. It had been the subject of my waking thoughts for many nights, and had occupied a large portion of my leisure hours. Matters remained thus unsettled until December 11. On this night I had not, to my knowledge, once thought of the subject, but I had not been long in bed, and _asleep_, when my brain was as busy with the books as if I had been at my desk. The cash-book, banker’s pass-book, etc., appeared before me, and without any apparent trouble I almost immediately discovered the cause of the mistake, which had arisen out of a complicated cross-entry. “I perfectly recollect having taken a slip of paper in my dream and making such a memorandum as would enable me to correct the error at some leisure time; having done this, the whole of the circumstances had passed from my mind. When I awoke in the morning I had not the slightest recollection of my dream, nor did it once occur to me during the day, although I had the very books before me on which I had apparently been engaged in my sleep. When I returned home in the afternoon, as I did early for the purpose of dressing, and proceeded to shave, I took up a piece of paper from my dressing-table to wipe my razor, and you may imagine my surprise at finding thereon the very memorandum I fancied had been made during the night. “The effect on me was such that I returned to our office and turned to the cash-book, when I found that I had really, _when asleep_, detected the error which I could not detect in my waking hours, and had actually jotted it down at the time.”