Note 17 — THE DREAMS OF THE BLIND

That even a comparatively slight disturbance of vision, affecting only a small portion of the visual experience, can leave a permanent trace upon the sight-centre is made very probable by a case (recorded by Dr. McCosh, Cognitive Powers, p. 106) of a young man whose defect consisted in his seeing everything double,—a defect which a subsequent operation removed. "If I attempt," he writes, "to recall scenes that I saw while my eyes were out of order, I invariably see them as they appeared during that time, although I may have seen them many times since the operation. For instance, in the case of the minister in the pulpit at home, I see two images of him, no matter how much I may try to get rid of one of them.... My recollection of the office in which the operation was performed, as also of everything in it, is double, although I saw it only twice before the restoration of my sight, and many times after. The objects which I have seen since the operation are always single when recalled."