VOICE AND SPEECH. 573 



kinsesthetic and cheiro-kinsesthetic center, fibers descend as part of 

 the pyramidal motor tract, those from the glosso-kinsesthetic center 

 going to the motor-speech apparatus in the medulla, and those from 

 the cheiro-kinassthetic center going to the spinal-motor ganglia con- 

 cerned in the act of writing. As is known, the auditory word-center 

 is in the first temporal convolution, the visual word-center in the 

 gyrus angularis and a part of the supramarginal gyms, the speech- 

 center in the third left frontal convolution, and the writing center 

 in the posterior part of the second frontal convolution. 



The auditory word-center is the first called into activity; then 

 the speech-center is gradually organized under the influence of 

 excitations coming from the auditory word-center. After a year or 

 two the child's visual word-center becomes organized, and the child 

 recognizes letters and words, and at the same time two sets of asso- 

 ciation-channels, commissural fibers, are laid down between the audi- 

 tory word-center and this visual word-center. Finally, the child 

 reads; then there must be activity first in the visual word-center, 

 then in the auditory word-center, and immediately afterwards in the 

 glosso-kinaesthetic center. Then, as the child learns to write, the 

 cheiro-kinaesthetic center becomes organized, the guiding influence 

 of the visual center being called into play, and this would lead to a 

 development of commissural channels between the two centers. The 

 visual center holds the same sort of relation to the act of writing 

 that the auditory word-center holds to articulate speech. In writing 

 from dictation, the train of activity starts in the hearing word-cen- 

 ter, spreads to the visual word-center, thence to the cheiro-kinaes- 

 thetic center, where the efferent stimuli pass over to the spinal motor 

 centers (Bastian, Allbutt's System of Medicine, vol. VIII). 



The chief varieties of aphasia are: 



, . f aphemia. 

 Motor aphasia < , . 



| agraphia. 



. . f visual. 

 Sensory aphasia < ,.. 



) auditory. 



Conduction aphasia. 



Auditory Aphasia. Supposing the patient's hearing is perfect, 

 en auditory aphasia is revealed by his inability to put out his 

 gue. 



Visual Aphasia (Alexia). Supposing the patient can see per- 

 fectly, can the patient understand written or printed words? If he 

 fails to do so, he has alexia. 



