168 Temporal Lobe and Auditory Areas [CHAP. 



We have next to consider the work of those who have attempted a subdivision of 

 cortical areas according to structural peculiarities, but unfortunately the evidence obtained 

 in this manner is quite fragmentary in character. For instance, localisation is not assisted 

 to any extent by Hammarberg's work, because all that he tells us is that the structure 

 of the superior temporal convolution differs from that of the remainder of the temporal 

 lobe, inasmuch as the cells of the layer of medium-sized pyramids and ganglion cells are 

 smaller, and isolated larger cells are present; of the recognition of definite areas there is 

 no note. 



Similarly, although S. Ramon y Cajal has supplied us with a fund of details on the 

 fine histology of the individual elements of the temporal lobe, his work yields little or 

 no information concerning topical variations. Also concerning the drawings reproduced by 

 both Hammarberg and Ramon y Cajal we are given only a rough idea as to the position 

 from which the sections represented were taken ; Hammarberg merely states that his drawing 

 is from about the middle of the first temporal gyrus, whether from the crown lip or side 

 is not mentioned ; and Ramon y Cajal's figure is vaguely described as having been taken 

 from a section of the first temporal gyrus. 



Also Kars, who has examined the fibre-constituents in the cortex of all parts of the 

 brain, does not give a clear account of the territorial differences in the temporal lobe, 

 although he evidently recognised the exceptionally large association fibres in the transverse 

 temporal gyri to which I have drawn attention. 



Judging from the fruitful results which attended Bolton's examination of brains from 

 cases of old-standing blindness, one would imagine that a similar examination of the 

 transverse and superior temporal convolutions in cases of deaf-mutism and long-standing 

 deafness of peripheral origin would prove equally profitable, but so far as I am aware this 

 is a task which nobody has hitherto attempted, and the sole information which we can fall 

 back on at present is the fact that in some cases of deaf-mutism the superior temporal 

 gyri have exhibited a certain amount of atrophy to the naked eye. (Mills and Broadbent.) 

 Of the importance of naked eye shrinkage, however, we have strong reasons for being 

 sceptical, and I fear that the information demanded on this point cannot be forthcoming 

 until serial sections of the auditory cortex, demonstrating the condition of both nerve cells 

 and nerve fibres, are made 1 . 



Lastly, I have to refer to certain subcortical bands which are supposed to possess the 

 function of uniting different parts of the temporal lobe with one another and with other 

 cortical centres. Of such bands the fasciculus longitudinalis inferior seems to be the most 

 important. It has already been alluded to in the chapter on the visual area, and probably 

 constitutes a band of association between the auditory and the visual areas; at the same 



1 Since writing tbe above the brain of a man, aet. 40, who had been deaf from birth, has come into rny hands, 

 and I have taken the opportunity of examining the temporal lobe in serial sections. The results are most gratifying, 

 because the sections stained with thionin show exquisite changes clearly concentrated on the gyri of Heschl, although 

 distributed to a certain degree and extent over the "psychic" field of cortex, and the posterior insula. 



A general disturbance of lamination, an absence of large pyramidal cells, and the predominance of numbers of 

 round nucleated elements looking like nerve cells deprived of body substance and processes, are the prevailing features, 

 and on the whole the changes closely resemble those I have seen and previously described in the post-central gyrus 

 in cases of Tabes Dorsalis. 



To this I might add, that what appear to be similar changes have been recently observed by Strohmayer in a case 

 of Congenital Deafness, but unfortunately I have been able to procure only an abstract of his report. 



