776 THE CEREBRAL CORTEX. 



it has been found that lesions of the temporal region, especially of the 

 first and second temporal gyri and of the gyrus supramarginalis, are 

 causative of the condition known as word deafness, 1 i.e. words although 

 heard are not understood, not " perceived," nor can words be recalled to 

 memory. An individual with such a defect is unable to speak or to 

 write intelligibly, although, if the visual centre is intact, he might be 

 able to comprehend written language. And, as Bastian has pointed out, 

 a lesion in the association fibres which connect the auditory word centre 

 with the speech centre, would be equally productive of the same 

 condition. 2 



Similarly, word-blindness (alexia) has been found to result from 

 lesions in or near the left occipital region, written language becoming 

 unintelligible, although spoken language may be comprehended. There 

 is in these cases necessarily a condition of agraphia. Further, in the 

 production of such acts as reading aloud or writing from dictation, both 

 the visual and the auditory word centres as well as Broca's centre and 

 the motor centres of the left hemisphere must all come into action, and 

 a lesion of any one of these or of the association fibres connecting them 

 one with another must be fatal to the proper performance of these 

 actions. The cortex of the island of Reil of the left hemisphere has been 

 supposed by Meynert to be a special association centre for language ; it 

 is better developed in the primates than in other animals, and has very 

 few callosal fibres uniting it with the cortex of the opposite island. 



Sensory aphasia may show itself as a defect in or loss of recollection 

 of words, especially of names of people or things, although the idea of 

 the thing is represented in consciousness (verbal amnesia), or it may 

 show itself as word-blindness or word-deafness, or as a combination of 

 two or more of these conditions. 3 



The Connections of the Cortical Centres with one Another 

 and with the lower centres. 



Connections of the frontal lobe and Rolandic area. — The Rolandic 



1 Wernicke, " Der aphasische Symptomenconiplex," 1874. Bastian appears to have 

 been the first to point out that aphasia may result from disturbance in an auditory centre 

 of the cortex ("On the Various Forms of Loss of Speech in Cerebral Disease," 1869), 

 although the position of such centre was at that time unknown, and its very existence 

 purely hypothetical. 



2 It is held by Herbert Spencer and by Bastian that words are revived in the cerebral 

 hemispheres, as remembered sounds or visual impressions. This view appears more 

 probable than that of "Wundt and Bain, which considers that words are revived as faint 

 impressions of the processes occurring in motor cells during their articulation. 



3 The subject of aphasia is far too large and the literature much too voluminous to be 

 dealt with here otherwise than in the briefest possible manner. The student is referred, 

 for an account of all the varieties which occur and a full discussion of the conditions under 

 which the different forms are produced, to the works of Bastian, " On the Various Forms 

 of Loss of Speech, etc.," 1869; "Brain as an Organ of Mind," "Paralyses, Cerebral, 

 Bulbar, and Spinal," London, 1886, and especially, "On Aphasia," etc., 1898 ; Wernicke, 

 "Der aphasische Symptomencornplex," Breslau, 1874, and Fortschr. d. Med., Berlin, Bde. 



Ziemssen's 



Lichtheim, " On 



, Bd. xvi. 



S. 654.; J. Ross, "On Aphasia," London, 1887 (which includes a brief and clear account 

 of the various views that have been taken to explain the several forms of aphasia) ; Cowers, 

 " Diseases of the Brain," London, 1893 ; Charcot, reported by Marie in Proqres mid., Paris, 

 1888, No. 5 ; Allen Starr, Brain, London, 1889, vol. xii. p. 82 ; Bateman," " On Aphasia," 

 London, 1890 ; Dejerine, Compt. rend. Soc. de biol., Paris, 1891 ; Shaw, Brain, London, 

 1893, vol. xvi. p. 492; Byrom Bramwell, "Morison Lectures," Edinburgh, 1900. In 

 several of these works the principal literature of the subject will be found referred to. 



