iv] I'osffi'iitrdl or tfenifory Area 101 



attribute as a capacity tin- tin- primary reception, elaboration and interpretation of sensory 

 stimuli streaming in from all parts of the body. 



Then, in regard to the opinion expressed by Ferrier, that the true sensory path lies in 

 system No. 2 of Flechsig's corticipetal fibres, it may be pointed out that, although some of 

 these fibres may proceed to the falciform lobe, many form elaborate connections with other 

 parts of the brain, parts which there is not the slightest reason for supposing subserve a 

 sensory function, excepting in a most indirect and subsidiary manner; further, in discussing 

 the development of the sensory system of fibres I have already mentioned that, although the 

 time is not ripe for drawing definite conclusions from published researches on this subject, 

 there are yet significant reasons for believing that Flechsig's system No. 1, which develops 

 first, is of more importance than system No. 2, and that it probably represents the continuation 

 of the main chain of sensory neurones, that is to say, the so-called "cortical lemniscus" of 

 von Monakow. Now it appears to me that Ferrier and Horsley and Schafer take insufficient 

 notice of this tract, and if the present view concerning its course be correct, namely, that 

 it ascends directly from the thalamic region to the postcentral gyrus, it obviously does not lie 

 far removed from the point of junction between the posterior and middle divisions ot the 

 limbic gyrus a part, by the way, which these observers admit to be especially vulnerable 

 and it is quite inconceivable how it can escape injury in such a radical procedure as removal 

 of that gyrus, and I think others will support my belief that the sensory disorders attending 

 such an operation are attributable to this complication rather than to any special virtue 

 possessed by the gyrus fornicatus. Clearly the foregoing objections also apply to certain cases 

 of tumour and haemorrhage involving either the anterior portion of the precuneus, the hinder 

 division of the paracentral lobule, or the subjacent and contiguous gyrus fornicatus, which 

 have been pointed to as favouring the view we combat. 



Tn his attempt to prove that sensation is centred in the limbic lobe to the exclusion of 

 the Rolandic zone, Ferrier brings forward an analysis of a series of 284 cases of lesion in the 

 latter region which he has collected from various sources, but the conclusion deduced from 

 those cases is criticised by von Monakow as follows : " since the majority of the observations 

 were made many years ago, and an exact description of the extent of the lesion is not forth- 

 coming, and since the methods by which the sensibility was tested leave something to be 

 desired, these statistics are to be received with caution"; and it may be gathered from remarks 

 made elsewhere that I consider von Mouakow's criticism justified. 



But, although I disagree with those observers who maintain that the centre for " common 

 sensation" is far removed from the central region, there is no getting away from the fact that 

 cases of superficial lesions in the central convolutions have been recorded and apparently carefully 

 tested, and yet no direct evidence of persistent sensory disability has been elicited, and hence 

 it is not surprising that Charcot and Pitres regarded the sensory changes which occur in cases 

 of lesion of the central convolutions as accidental and unessential phenomena, and that Ferrier, 

 Nothnagel, and others should be of the same opinion. At the same time we cannot consider 

 this question closed until we are provided with confirmatory results from an analysis of a 

 fresh series of cases ; for, as von Monakow has pointed out, and as even Ferrier's words 1 

 support, a lesion in the Rolandic area will be more likely to bring about impairment of 



1 Of the 284 cases of lesion of the Rolandic zone collected by Ferrier, the state of the sensibility was not mentioned 

 in 100, in 121 it was said to be intact, and in 63 there was some impairment; "in 28 of these, however, the lesion was 

 not strictly confined to the Eolandic area, but implicated the adjacent lobes, especially the parietal." 



