VI J SIIIIUIHII-I/ a IK/ Conc/itsioiix 171 



as sonic assume, it may be taken for granted that more proved cases of complete one-sided 

 deafness in consequence of a contralateral temporal lesion would have been reported, but as 

 it is, the paucity of such cases and the unreliable nature of the few that have been 

 published is a weighty negative point against that assumption. 



Leaving the transverse temporal gyri we have now to deal with the question of the 

 existence of a second centre, specialised for the interpretation and further elaboration of 

 primary stimuli : and in the next few lines I shall indicate not only that such a centre 

 probably exists, but that in all likelihood it is distributed over the area already described 

 as forming a skirt for the audito-sensory area. Now the truth that this field possesses a 

 special structure resembling but not identical with that of the audito-sensory cortex, and 

 one which makes it readily distinguishable from that of more outlying parts, seems to me 

 to be one of the strongest reasons for supposing that it is endowed with a specific function ; 

 and since in our examination of the visual, and also of the motor area, we found that the 

 primary centre was invested or fringed in a similar manner by a belt of cortex to which 

 \ve assigned psychic properties, so also in the case of the auditory area it should not be 

 considered a transgression of the bounds of ordinary possibility to assume that the investing 

 field has a psychic function. 



Without an inspection of numerous sections stained by the method of Golgi and other 

 processes, a task which I have been unable to undertake, as all m^ time has been occupied 

 in studying the cortex from the topographic standpoint ; also without an examination of 

 the brain in favourable cases of deaf-mutism, and under conditions in which an interference 

 with the chain of auditory neurones somewhere in its central course has given rise to 

 degeneration, or retrograde atrophy, of the nerve fibres leading to the auditory area and 

 the cortical cells with which they form connections, it would be premature to offer any 

 statement concerning any special elements in this investing field of cortex, which may be 

 singled out as bearing a direct relation to the psychic function ; at the same time it may 

 not be out of place to note some of the probabilities which the appearances presented by my 

 sections suggest. 



In referring to the outstanding histological characters of the cortex covering the 

 transverse temporal gyri, I have mentioned that an homologous structure exists in another 

 sensory centre with the histology of which we are more familiar, namely, the visual. The 

 question then arises whether the homology can be extended to the investing or audito-psychic 

 area, and I think it can : for just as in the visuo-psychic area, the large, deeply-placed, 

 oblique fibres lose in prominence, so it is in the audito-psychic; and just as in the visuo-psychic 

 area the fibres of large calibre tend to be incorporated in the radiary fasciculi and the 

 whole interradiary field shows a fibre-wealth which is infinitely greater than that of more 

 outlying parts, so it is also in the audito-psychic area. But when we come to a comparison 

 of the cell-arrangement, the homology is not so satisfactory; for although the large supra- 

 stellate pyramidal cells, which I look upon as possessing a special significance, are on the 

 whole markedly larger and possess a different form and staining reaction from the same 

 cells in more outlying fields, they do not stand out so prominently as the large cells 

 noted in the visuo-psychic area ; nor again is the general cell-arrangement very different 

 from that met with in the transverse temporal gyri ; however, it must be noted that scattered 

 along the external layer of large pyramidal cells there do exist cells of outstanding size, 



22 2 



