864 THE CENTRAL NERVOUS SYSTEM 



To quote Bolton again, ' ' In such cases deafness is therefore a more serious 

 deprivation than blindness, as, for the evolution of the functional activity 

 of the cerebrum, an entirely new development of associational spheres to 

 replace those normally employed for auditory and spoken language has 

 to be acquired. In the case of congenital or early-acquired blindness, on 

 the other hand, the complex sphere of language, with all its psychic com- 

 ponents, can be employed in a perfectly normal manner and almost ex- 

 actly as it is brought into use in. the case of persons who neither read nor 

 write." 



It would be beyond the scope of this work to go into the clinical and 

 pathological evidence upon which Marie bases his far-reaching conclusions. 

 Suffice it to say that it is definitely shown that the old contention of Broca, 

 that a special speech center exists, is entirely unjustified by the facts of 

 clinical and pathological experience. Broca, it will be remembered, con- 

 tended that motor aphasia is always due to destructive processes occurring 

 in the lower portion of the ascending frontal convolution on the left side, 

 and he concluded that this portion of the cerebrum represents the speech 

 center. Marie has shown, however, that a patient may show distinct evi- 

 dence of aphasia without any lesion involving this so-called Broca area, 

 and, on the other hand, that cases not infrequently occur in which this is 

 completely destroyed without any evidence of aphasia. Important though 

 this discovery of the inaccuracy of Broca 's conclusion is, by far the most 

 important conclusion which we may draw from Marie's work is that, since 

 language is a product of an extended integration of impressions and 

 memories stored in different parts of the cerebrum, it is not so likely to be 

 interfered with by destruction of any one of the centers as it is by destruc- 

 tion of the paths which connect the centers with one another. As a matter 

 of fact, Marie has shown that in cases of aphasia the lesion is nearly 

 always located in the course of the pathway connecting the visual and 

 auditory centers with the other centers of the cerebrum ; it lies around the 

 upper end of the fissure of Sylvius in the region which in previous years 

 had been considered particularly associated with the condition known as 

 sensory aphasia. Those interested in this subject should consult Bolton 's 

 article. 



