SENSE AREAS AND ASSOCIATION AREAS. 207 



may be imagined that the individual suffering from word-blindness 

 alone is essentially in the condition of one who attempts to read 

 a foreign language. The power of vision exists, but the verbal 

 symbols have no associations, therefore no meaning. So one who is 

 word-deaf alone may be compared to the normal individual who is 

 spoken to in a foreign tongue. The words are heard, but they have 

 no associations with past experience. 



The general facts regarding aphasia illustrate excellently the 

 modern conception of cerebral localization. The understanding 

 and the use of spoken or written language is, so to speak, a mental 

 whole, both from the standpoint of education and of use. To 

 understand or to express certain conceptions implies the use of 

 definite words, and our visual, auditory, and motor experiences are 

 combined in these symbols. Each phase of this complex may be 

 cultivated more or less separately; in the case of the unlettered 

 man, for instance, the written or printed symbols form no part 

 in the associations connected with his verbal concepts. Corre- 

 sponding to these facts we have, on the anatomical side, a portion 

 of the brain in which the auditory memories are organized, that 

 is, connected in some way with a definite arrangement of nerve 

 cells and their processes, another part in which the visual memories 

 are organized, and other parts in which the motor memories as 

 regards speaking or writing are laid down in some definite form. 

 Each part is a distinct center, but their combined use in intellectual 

 life would imply that they are connected by association fibers, so 

 that, although fundamentally distinct, they are practically com- 

 bined in their activity. Corresponding with this conception it is 

 found from clinical experience that aphasics, although the lesion 

 may affect only one of these various centers, suffer a deterioration, 

 more or less pronounced, of their general intellectual capacity. 

 We may conceive that the varying gifts of individuals, in the 

 matter of the use of language, rest partly on the amount of train- 

 ing received and partly on the inborn character and completeness 

 of the nervous machinery in the different centers. 



The Association Areas. According to the views presented 

 above, it will be seen that the motor and sense areas occupy only 

 a small portion of the cortex, forming islands, as has been said, 

 surrounded by much larger areas. Flechsig* has designated these 

 latter areas as association areas, and has advocated the view that 

 they are the portions of the cortex in which the higher and more 

 complex mental activities are mediated, the true organs of thought. 

 His views as to the relations and physiological significance of these 

 areas have been based chiefly on the study of the embryo brain 



* Flechsig, "Gehirn und Seele," Leipzig, 1896; also, "Archives de neurol- 

 ogie," vol. ii, 1900. 



