CHAP. XXIX.] SPEECH AND THOUGHT. 647 



The three principal cases recorded in this section are 

 particularly important from a psychological point of view. 

 They enable us to trace Will or Volition to its sources 

 when we find persons unable to Will an act in response 

 to a Visual Impression, though they can at once and 

 without hesitation effectively Will the same act in response 

 to a related Auditory Impression or vice versa (pp. 353, 

 355). 



B. APHASIA. 



5. Damage to the first parts of the outgoing tracks 

 leading from the Cerebral Word-Centres to the left Corpus 

 Striatum. 



Hitherto we have been considering defects resulting 

 from abnormal conditions of the Auditory and Visual 

 Word-Centres themselves, or from injuries to their 

 ' afferent ' or ' commissural ' fibres ; now we turn to the 

 illustration of the results following upon injuries to the 

 ' outgoing ' fibres from these and from the Kinaesthetic 

 Word-Centres those which bring them into relation with 



given, and affording also some information of the kind referred 

 to. Of this patient it is said : " He could write very well from 

 dictation, but shortly after he was unable to read the words he had 

 written, and he suffered in general from complete alexia [i.e. 

 inability to comprehend written symbols]. By means of a 

 stratagem, however, as he himself very clearly explained, he suc- 

 ceeded in reading the word he had written from dictation upon the 

 tablet. He passed his finger over each letter of the written word 

 as if he were writing it again and read it while so doing. He then 

 made a sort of calculation and counted off the sum' of the separate 

 letters." Here apparently the Kinaesthetic Impressions from. 

 Writing-movements were capable of rousing related parts of the 

 Auditory Word-Centre so as to enable them to act through the 

 other portion of the Kinaesthetic Word-Centre, and thus evoke 

 Speech-movements. 



