678 Dynamic Theory. 



Singularly enough he could write as well as ever, but it was impossible 

 for him to read what he had just written. The memory of the motion 

 involved in producing a letter, remained, the memory of its appearance 

 was gone. Observe, therefore, that it was a portion of his sight mem- 

 ories that were gone, through sudden disease of a portion of the cells 

 in the posterior lobe, and, since there was blindness in the right half of 

 the eyes, the disease was located in the right hemisphere of the brain. 

 (See fig. 369. ) The memory of the motion used in writing, served to 

 take the place to some degree of the lost memory pictures, for when 

 asked to read a word, he would bring up his hand to the page, and with 

 his finger trace the form of the letter, and then name it. It was evi- 

 dent that the only means he had of recalling a letter was by going 

 through the motion necessary to write it ; in other words, by calling 

 into play his motor memories. As he was more accustomed to trace 

 written than printed letters, it took him a longer time to recall printed 

 words by tracing them, than written ones. But this was not his only 

 defect of memory. He found that many objects, formerly perfectly 

 familiar, were no longer recognized by sight. He had been well ac- 

 quainted with the streets of Paris, but on going out now he looked at 



FIG. 369. Scheme of the Optic Tracts, showing 

 connection of the Organs of Vision, in the Cere- 

 brum, with the Retina. The lines indicate the 

 connections, O being connected with the right 

 half of each eye, and O with the left half of each 

 eye. The Angular Gyri, A, A', are connected with 

 the central parts of the eye, especially the Mac- 

 ula Lutea ( yellow spot ). Each gyrus is connected, 

 chiefly with the eye of the opposite side, but also, 

 to a minor extent, with the eye on its own side. 

 For position of the angular gyri,see fig. 360, A (jr. 



E Right Eye. 



f. Left Eye. 

 , N'. Optic Nerves. 

 C. Optic Chiasm. 

 T, T .Optic Tracts. 



A. Right angular gyrus in cortex of cerebrum. 

 A Left 



O. Right occipital lobe of cerebrum. 

 Left 



the houses and streets as those of a new, 

 unknown city, and he was unable to find 

 his way about. The loss of memory did 



FIG. 369. not 'consist simply in a failure to recog- 



nize objects seen, it involved his power to recall objects formerly well 

 remembered, places well known, faces, scenes of his childhood, &c. 

 His other mental faculties, perceptions and memories, were not impaired, 

 and he was not paralyzed, but he was put back as to a large proportion 

 of his sight memories. These memories were gone, but he still retained 

 the power of seeing, and therefore the power of acquiring a new stock 

 of memories. As to reading, he had been put back into the exact con- 

 dition of a boy just beginning to learn, and he was seen by Dr. Star 

 " in the wards of Charcot's great hospital in Paris, studying away at 



