in] Post-amputation ('IKUKJCK in the Cerebral Cortex 51 



movements lie; and, having gained this much information, we can, from our knowledge of 

 localisation in the anthropoid brain, form a fairly correct idea concerning the disposition 

 of cells controlling other movements. 



And provided sufficient care be exercised in the examination of such material, there 

 seems to be no method applicable to the human brain, with the exception of electrical 

 excitation of the cortex, and chances for practising this rarely occur, which is better adapted 

 for purposes of precise and correct localisation. Comparing it for instance with other means 

 to localisation, it of course cannot be denied that we have derived valuable information 

 from a clinical study of the effects produced by natural lesions, such as cerebral softening, 

 cerebral tumour, traumata, etc., but it is equally true that the proportion of cases in which 

 any of the above-mentioned lesions have been so limited in extent and so pure in effect, 

 as to admit of a precise judgment concerning delicate points in differential localisation, is 

 exceedingly low. Given, on the other hand, a case of section of the nerves supplying even 

 a single group of muscles, for instance, the extensors of the foot, I maintain that it would 

 be quite possible from a careful examination of the cortex and a study of the resulting 

 " reaction a distance " to determine the exact distribution of the motor elements, on the 

 integrity of which, movements of that particular group of muscles depended, and, by col- 

 lecting and examining a selected series of similar cases and collating the results with the 

 findings of the physiologist, the clinician, and embryologist, we may eventually hope to 

 draw on the surface of the human brain a detailed map of motor localisation, so definite 

 and so exact, that it will not require alteration and revision at the hands of our successors. 



Method of Examination. 



In case No. 2, the brain was hardened in Orth's solution and the entire Rolandic area 

 cut seriatim into sections, 15 /a in thickness, and every fifth specimen was stained with 

 thionin and examined. In the remaining instances, the brain was hardened in formol and 

 the method for the examination of the brains from the cases of amyotrophic lateral sclerosis 

 followed 1 . 



CASES OF AMPUTATION OF THE LOWER EXTREMITY. 



CASE No. 1. 



The first case I have to record is that of a female, aet. 67, whose left leg had been amputated at the 

 knee joint ; the date of the operation was not ascertained and is merely indicated in the clinical notes to 

 which I have had access by the remark " some years." 



Both hemispheres were examined, and whereas the left was normal, no difficulty was experienced in 

 defining an area of degeneration in the right. 



In those sections of the affected hemisphere which passed through the small area of motor cortex, on 

 the mesial surface, and also the oitermincius portion of the same field, at the margin and on the convexity 



1 In the examination of two of these hemispheres I was fortunate in securing the cooperation of mv two colleagues, 

 Doctors A. C. Wilson and H. E. Brown, and it was a great source of satisfaction to obtain by this means an 

 independent confirmation of the correctness of my results, for following my methods, these gentlemen, in both 

 specimens, easily recognised the characteristic cell changes and succeeded in mapping out fields which agreed, in 

 the minutest particular, with the ones I had defined. 



72 



