56 Precentral or Motor Area [CHAP. 



The right and left hemispheres were examined and both displayed the same changes. On account of 

 the greater length of time which had elapsed after the amputation, it is not surprising that the changes 

 found differed materially from those observed in the two previous cases. Three varieties of altered cells 

 were noticed. (1) A few showed an absence of cbrumuphilic elements, a dislocated nucleus, a rotund figure 

 and an absence of all processes, save the apical, and so far agreed with cells noticed in previous cases, 

 but they differed in one important respect, instead of being swollen they were reduced in size. Now this 

 reduction in volume I am forced to regard as a manifestation of post-reactive atrophy and a change of 

 more recent date than that represented by the next variety. (2) These were shrunken, pallid but heavily 

 pigmented objects, having an irregular contour, present in abundance and plainly representing the last stage 

 of giant cell destruction. (3) A number of giant cells were observed which were obviously reduced in size, 

 which had a serrated contour and short, sinuous and attenuated processes, and which were specially curious 

 in staining very intensely, so intensely and universally that it was quite impossible to recognise Nissl bodies, 

 nucleus or nucleolus in them. To my mind there can be little doubt that these represented another 

 condition of late atrophy, and the opinion which I would venture to offer concerning them is that they 

 pertained to nerve fibres proceeding to some muscles situated above the amputated level, muscles which had 

 become atrophied from disuse, in spite of integrity of their nervous supply. 



In point of numbers, I must say that there was not so great a reduction in the cell aggregate as I 

 expected, and this in spite of the very severe character of the degenerative changes shown. It is also to 

 be mentioned that destruction of cells in other laminae, and interference with the columnar arrangement, 

 though noticeable to a certain extent, were not nearly so obvious as they were in the cases of Amyotrophic 

 Lateral Sclerosis. 



The distribution of the affected area closely resembled that observed in case No. , in which the 

 amputation was at the same level (text-figure 4). As specially involved parts, the whole of the area on 

 the mesial surface, that part lying exactly along the upper margin of the hemisphere, and the cortex on 

 the anterior wall of the upper centimetre of the fissure of Rolando, were singled out. The giant cells on 

 the free surface of the upper extremity of the precentral gyrus, that is, the external members of Bevan 

 Lewis and Clarke's large uppermost group, had in large measure escaped, as also had the cells of the 

 smaller group a little lower down. From which it would appear that these two groups are mainly concerned 

 with the control of thigh movements; for it is to be remembered that in case No. 1, where the flexors 

 and extensors of the knee were thrown out of action by amputation at that joint, these groups showed 

 marked signs of retrograde degeneration. 



CASES OF AMPUTATION OF THE UPPER EXTREMITY. 



CASE No. 1. 



Male, aet. 63. Amputation of the 1 right upper arm at the junction of the lower and middle thirds, 

 two years prior to death. 



Examination of the paracentral lobule and of the precentral gyrus, as far down as the great annectant 

 buttress, was not attended by positive results, only occasionally a giant cell was seen showing changes 

 suggestive of "reaction h distance," and this scattered degeneration may be more reasonably regarded as 

 senile and physiological in character than as having anything to do with the amputation. 



At the buttress, also, no pathological change was observed. On coming, however, to the group of cells 

 which lay immediately below, a large number of elements were seen which, although they did not exhibit 

 the changes of "reaction k distance," were yet reduced in size and stained so uniformly and intensely that 

 their intimate structure could not be made out. 



There next came a long series of sections reaching from here to within a few millimetres of the lower 

 genu (in this brain placed on a level with the inferior frontal sulcus) in which there was much more 

 evidence of disease, at the same time the changes were not nearly so pronounced as in the cases of leg 

 amputation, for only about 20% of the cells exhibited the change "reaction a distance" in its typical 

 fully-developed form; 50%, however, presented appearances which I took to be indicative of immature 



