Page:Popular Science Monthly Volume 25.djvu/631

Rh longer time to recall by tracing printed than written words. But this was not bis only defect of memory. He found that many objects formerly perfectly familiar were no longer recognized by sight. He was well acquainted with the streets of Paris, but on going out he now looked at the houses and streets as at those of a new, unknown city, and he was unable to find his way about. The loss of memory did not consist simply in a failure to recognize objects seen, it involved his power to call up to his mind objects formerly well remembered, places well known, faces, scenes of his childhood, etc. The blindness in the right half of both eyes indicated that the disease was situated in the posterior part of the left half of the brain, for this has been found diseased in nearly thirty cases of similar defects in vision in which an examination of the brain was made. The loss of memory of objects seen indicated that in that part of the brain in which the perception by sight occurs were located nerve-cells whose integrity was necessary to the existence of the sight-memories lost. The case demonstrated conclusively that sight-memories lie in the posterior part of the brain. The mental vigor of this man was good. His other faculties, his other perceptions and memories, were not affected. He was not paralyzed; but, as far as reading was concerned, he had been put back into the exact condition in which he was when as a boy he began to learn to read. And when the writer saw him last, in the wards of Charcot's great hospital in Paris, he was studying away at his alphabet like a school-boy of six years.

This is not an isolated case. In the same hospital, at the same time, was another gentleman who had been remarkable for the excellence of his memory. It had always been possible for him to acquire easily, and he had only to read a passage carefully in order to remember it verbatim. He also had considerable talent in sketching, and was in the habit of drawing any figure or view which pleased his eye. His memory of music, or of things heard, was less active and reliable than his visual memory. One day he suddenly noticed a peculiar change in his power of mental action, which alarmed him very much. He found that everything about him seemed strange and unfamiliar. His visual memory was entirely gone, so that he no longer recognized objects or faces, and could not call up to his mind the forms or colors of well-known things. The town in which he lived seemed an unknown place. Ho looked at its streets, its houses, its statues with curiosity, as at those of a strange city. The same was true of Paris, to which he came for medical advice, and where to his surprise he could not find his way about. At the same time he lost the power to sketch, being unable to remember the object to be drawn long enough to draw it, and being unable to recall the appearance of lines and shading in a picture. He found that he could not recall the faces of his wife and children, and when they came to him he only