Memory. 679 



his alphabet like a school boy of six years. " It is important to observe 

 in regard to this case, that it confirms the opinion elsewhere expressed, 

 that mental operations may be carried on by one cerebral hemisphere 

 alone. * The fact that this man became blind in one-half of each eye, 

 proves that the whole of that part of the sensory sight tract in the oc- 

 cipital lobe of that side, was ruined, both as to the actual and the po- 

 tential areas. Because, if the potential area, or any part of it, had re- 

 mained, he would not have been blind on that side, but would have sim- 

 ply forgotten the meaning and relationship of one-half of the billiard 

 ball. But very evidently he had been accustomed to see the ball by 

 both hemispheres, one-half by each. The disease was located in the oc- 

 cipital lobe, and the angular gyrus of the right side. By consulting 

 the diagram (fig. 369) it is seen that the disease of the occipital lobe, 

 0, would destroy vision memories of the right side of each eye. Dis- 

 ease of the angular gyrus ( A) on the same side would destroy the mis- 

 cellaneous memories originally stimulated by the central part of the 

 eyes, the yellow spot. It would seem in this case that most of these 

 memories were monopolized by the angular gyrus of the right side, so 

 that upon its failure the visual memories vanished. But he could see, 

 probably with the uninjured left side, and with it he could lay in a new 

 stock. 



Another Case : In the same hospital, at the same time, there was an- 

 other gentleman who had suddenly lost his visual memory, so that he 

 no' longer recognized objects or faces, and could not recall the mem- 

 ories of the forms or colors of the most familiar things. The town in 

 which he lived seemed an unknown place, and he looked upon every- 

 thing as a stranger would. He did not know his wife and children ex- 

 cept by their voices, and he even forgot his own appearance, and being 

 in a large public gallery and seeing, as he supposed, some one in a door- 

 way, barring his passage, he stepped forward to ask the stranger to let 

 him pass, when, by the motions, he realized that it was his own figure 

 seen in a large mirror. This loss of visual memory extended to mem- 

 ories of his childhood, as well as to those acquired recently. In read- 

 ing a book, or adding a column of figures, it was necessary to do it 

 aloud so that the sound memories could help to make him understand. 

 While formerly he could remember easily what he read, he was now 

 obliged to read aloud anything he desired to commit to memory, and 

 thus to learn it by impressing his auditory memory. An interesting cir- 

 cumstance was, that in his dreams he no longer saw objects, but merely 

 heard sounds or words. He was an artist, and of course the loss of the 

 memory of all that he had ever learned of form and color, and all the 

 skill and taste depending upon remembered experience, worked an en- 



*This opinion is held by Longet, who cites, in proof , cases of injury to one hemi- 

 sphere without impairment of intellect. See Austin Flint, IV, 857. 



