Handbook of insanity for practitioners and students . or temporo-sphenoidal convolution. It was also supposed that thelocalization of aphasia in the left hemisphere was ren-dered doubtful by the observation of cases of aphasia afterlesions of the right hemisphere, but this doubt was relievedby the proof that the latter cases occurred in left-handedindividuals, who favor the right hemisphere by the move-ments of the left hand. The function of speech is complicated, and it is neces-sary to distinguish several varieties of aphasia. The lossof the power of hearing words causes word-deafness; that•
Handbook of insanity for practitioners and students . or temporo-sphenoidal convolution. It was also supposed that thelocalization of aphasia in the left hemisphere was ren-dered doubtful by the observation of cases of aphasia afterlesions of the right hemisphere, but this doubt was relievedby the proof that the latter cases occurred in left-handedindividuals, who favor the right hemisphere by the move-ments of the left hand. The function of speech is complicated, and it is neces-sary to distinguish several varieties of aphasia. The lossof the power of hearing words causes word-deafness; that•of reading, word-blindness; the loss of articulate speech APHASIA. 13 causes motor aphasia, and of the power of writing two latter groups contain the principal modes of ex-pression of human speech. Gestures accompany speak-ing, and both are usually lost at the same time, so thatpantomime need not he considered separately. The viewswhich generally obtain at the present time are shown inFig. 10, and comparison with Fig. 7 shows that the. Fig. 6 (After Ballet) . —a, The region of print images; p, the region of lan-guage images; y, the region of the speech images; S, the region of writing images. speech-centres are situated between the centres for move-ments and special sense-impressions. This arrangementseems to show the close relation of speech to all the othercortical functions. All four speech-centres are suppliedby the middle cerebral artery, which, however, also sup-plies other centres. The manifold character of the symptoms of aphasia ispartly explained in the manner just indicated, but somecases cannot be explained by anatomical considerationsalone, and require psychological examination. Speech isan internal and external process, composed of conceptionsand words. Aphasia shows that the word does not neces-sarily accompany the conception. The word is a collectivenotion, arising from the combination of several varietiesof images (auditory, visual, speech, and
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