170 Temporal Lobe and Auditory Areas [CHAP. 



possession of a specialised cell lamination, so also in the central auditory mechanism we 

 find a similar tract of fibres limited in its distribution to the transverse temporal gyri 

 of Heschl and their immediate neighbourhood, a part also containing cell-elements differing 

 from those found in any other temporal convolution. In the case of the visual function, 

 valid reasons have been produced for assuming that the restricted calcarine area is that to 

 which sight stimuli primarily pass; and since in the area of cortex believed to preside over 

 audition, we have an arrangement which from the anatomical point of view is closely 

 homologous, the deduction necessarily follows that the restricted transverse temporal area is 

 the part of the temporal lobe on which auditory stimuli first impinge. 



(3) If the assumption be correct that this area forms the arrival platform of auditory 

 stimuli, it of necessity follows that total deafness should attend either its bilateral obliteration 

 or a bilateral interruption of the system of fibres leading to it. It is to be regretted that 

 the clinico-pathological evidence which we are able to adduce on this point is not so 

 sufficing and convincing as it might be. The hindrances to the obtainment of the necessary 

 information are again of an anatomical character, for in nature we have to depend on 

 obstructive vascular lesions, tumours, subcortical haemorrhages and the like, to supply us 

 with our focus of destruction : but unfortunately a destructive process which will comply 

 exactly with localisation in regard to extent must be looked upon as an anatomical rarity, 

 and it is vain to hope that by a happy combination of circumstances such a case will fall 

 into the hands of one competent to report on it, both clinically and anatomically. 



Since cases showing the lesion we desire are denied to us, we are obliged to fall back 

 on cases which approximate thereto, and for support on my point I have gone through the 

 reports of five instances recorded in the literature of cases of complete cortical deafness 

 followed by an autopsy. And although the anatomical accounts of some of these cases do 

 not contain all the details one desires, the broad fact remains that in all, more or less 

 widespread bilateral lesions existed, having the hinder part of the superior temporal 

 convolution as a centre ; again, although it is not always stated that the transverse temporal 

 gyri were involved in the destruction, still observations to the effect that neighbouring parts, 

 like the insula, the supramarginal gyri, or the opercular part of the ascending parietal 

 convolutions, were included in the loss of substance, render it likely that this was the case. 



It is also unfortunate that the experiments which have been recorded do not assist to 

 any appreciable extent in enabling us to arrive at a definite conclusion on this point, but, 

 as already indicated, I think that if those experimenters who attempted to ablate the 

 auditory area had centred their operation on a destruction of the transverse temporal gyri 

 the results would have been less contradictory. 



Likewise no evidence one way or the other is to be obtained from a study of cases of 

 unilateral lesions of the special area under consideration, for here again opinions differ. 

 However, since an examination of published cases of unilateral lesions shows that those in 

 which a bilateral dulling of the sharpness of hearing was noted outweigh those in which 

 complete contralateral deafness has been reported, I am inclined to follow writers who believe 

 that each cortical auditory centre is connected with both ears and that an arrangement 

 exists analogous to that which obtains in the case of the visual apparatus. Although it 

 is difficult, almost impossible, to prove that one centre is more directly concerned with the 

 reception of stimuli from one ear than the other, yet the possibility of a preponderant 

 crossed association is not to.be lost sight of; if, however, this crossed association be absolute, 



