SENSE AREAS AND ASSOCIATION AREAS. 209 



two conditions may occur together, but cases are recorded in which 

 they existed independently. It 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 

 prevalent 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 believe that the varying gifts of individuals, in the matter 

 of the use of language, rest partly on the amount of training re- 

 ceived 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. 

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