iv] I'ofifcciitrtd or Sensory Area 87 



EXAMINATION OF NERVE CELLS. 



The examination was conducted on my usual plan, and the field inspected embraced the paracentral 

 lobule and entire "Kolandic area," the whole of the parietal lobe, the precuneus, and the posterior half of 

 the gyms fornicatus (riilc Plate IX), and a perfect display of the nerve cells was obtained in spite of the 

 fact that the braiu had been treated with a chrome salt. 



It will be convenient to begin with a detailed account of the cortical changes which I take to be 

 peculiar to this disease; these were found on the Rolaudic wall and edge of the postcentral gyms, and the 

 following description refers to parts in which the alterations were seen in their most typical form. 



Under a low power of the microscope, attention was attracted to the affected field by the following general 

 changes. An extraordinary condensation or huddling together and distorted arrangement of cells, a difficulty 

 in defining the various laminae, and a remarkable deficiency in cells of large size, added to which was a 

 noticeable reduction in cortical depth. (Plates VII and VIII.) 



Inspecting the laminae seriatim : 



The plexiform layer perhaps contained au excess of nucleated elements but did not seem to be the seat of 

 special disturbance. 



The cells in the second layer were numerous but many of them had lost their pyramidal shape and the 

 main process instead of looking upwards pointed in any direction; also the lamina was unduly beset by small 

 round cells. 



It was the same with the medium-sized pyramidal cells. Although elements pertaining to this category 

 were present in abundance, their columnar arrangement was disturbed, and their processes in the majority of 

 instances stunted, and again small round cells were superabundant. When compared with the normal part 

 one further noticed that the matrix intervening between the individual cells was greatly reduced in extent, 

 and this it was that accounted for the huddled-up appearance of cells above-mentioned. Now this alteration, 

 not confined, by the way, to the layer under consideration, is one of great interest and importance, but to what 

 the apparent condensation was due it was not easy to say. It was not altogether the result of disappearance 

 of medullated nerve fibres, because these, as I shall show later, were fairly well represented ; but that the 

 absorption and disappearance of dendritic processes, the finer extensions of which are unstainable by the 

 Nissl method, had a lot to do with it, there could be no doubt ; for these, as we know, weave their way in 

 and about the matrix and must contribute in no small measure to its general stability. Whether the con- 

 densation was associated with neuroglia changes I cannot tell, because 1 did not stain specially for these bodies; 

 also the influence of possible changes in the substance remaining, when neuroglia, nerve cells and fibres are 

 abstracted, can only Vie surmised. 



Of the large external pyramidal cells, not only were there none in a normal condition, but few of any 

 kind could be identified. The cells which one took to be the remnants of this lamina were deprived of 

 processes, of irregular shape and chiefly composed of a persistent nucleus, which in some instances stained 

 as deeply as the scanty surrounding protoplasm. At this level there was again an excess of small round cells. 

 Taking all in all, the disappearance of these large external pyramidal cells may be regarded as the most 

 important of all the cortical alterations. 



The lamina of stellate cells had lost definition, not so much because of a reduction of its normal cell- 

 wealth, but on account of changes in the layers immediately above and below, and especially because the 

 latter layers contained such a number of altered elements of the same size as stellate cells. 



The internal layer of large pyramidal cells, like the outer layer, suffered severely, but at the same time 

 normal elements were discoverable in it, albeit at rare intervals. 



The layer of fusiform cells appeared to share the general changes. 



In regard to the sectional extent of the diseased cortex, it is very important to mention that it was 

 practically confined to the Eolandic wall and edge of the gyrus. It rarely reached quite to the floor of the 

 sulcus ; and when the inspection was carried surfacewards on to the crown of the gyrus and to the inter- 

 mediate postceutral cortex, it was interesting to see how the lamination rapidly assumed a normal character. 

 (Plate IX.) 



