m] Post-fiiiij>ttf<ifi<>n C/ittiii/rn In the Cerebral Cortex 53 



characterising the normal cell, was taken by exceedingly fine dust-like granules, which, in thiouin prepara- 

 tions, gave the substance of the cell a pale greyish-purple, or when there was an excess of pigment, a 

 greyish-green colour. In some instances, the chromatolysis, for such it undoubtedly was, was general in 

 distribution, but it was commoner to find just a few chromophilic elements remaining and resisting the 

 disintegration, at the origin of the apical shaft, that is, in the uppermost part of the cell body; and, from 

 an examination of many cells, we satisfied ourselves that the process of destruction commenced in the 

 neighbourhood of the point of origin of the axon, and spread from there upwards; and \ve were also 

 'minced that the immediate surroundings of the nucleus constituted a specially vulnerable area, for so-called 

 central chromatolysis, which we took to lie an indication of minor or commencing "reaction," was frequently 

 observed It is a somewhat curious fact, that the destructive process seemed to leave the normal pigment 

 of the cell intact, for even in bodies which had reacted to an extreme degree this material could be seen 

 extending in the shape of a dense, sharply -defined cloud across the basal part of the cell, or lying in a 

 clump at the apex, and indeed it was more clearly visible in these degenerated elements, and especially 

 when the sections had faded with keeping, than in the normal cell. On account of this individual's age 

 67 years the conditions for the study of this pigment were of course exceptionally favourable. 



Comparing tracings of these degenerated elements with ones of normal cells from the same situation, 

 it was at once noticed that enlargement had occurred, not a great amount but a degree which we could 

 fairly estimate at 207,,, and quite enough to impart to the cell a globose, swollen, inflated appearance. 

 The outline of the body was regular, that is to say, free from serration or indentation, but the array of 

 long and stout lateral projections, normally existent, was greatly reduced, and those remaining were short, 

 attenuated and pale from loss of chromatic elements. An excess of pericellular small nucleated bodies was 

 occasionally seen. 



Dislocation of the nucleus was a very constant accompaniment of the chromatolysis, and this structure 

 was usually seen lying at the periphery of the cell above the equatorial line, although it did occupy other 

 positions. A certain amount of enlargement of the nucleus also occurred, and one or more indentations 

 were sometimes seen to cause bights in its normal circular or oval outline. A nucleolus was almost 

 invariably recognisable and occasionally enlarged. 



From this description, it is evident that the cytological conditions we had to deal with in this case 

 were identical with Mariuesco's " reaction k distance," and it is from a study of elements unmistakeably 

 diseased and showing a fully-developed degree of reaction, that the area which I shall now describe has 

 been mapped out. Vide text-figure 4. 



The affected field was situated at the upper end of the motor territory. On the mesial surface of the 

 hemisphere, the distribution of Betz cells followed the usual plan and altered members were found throughout 

 this part of the area 1 . On the coterminous upper part of the ascending frontal convolution they were again 

 found, and the degenerated area descended this gyrus for a distance of about 2 cm., stopping at a point 

 above the level of the superior frontal sulcus and about 2 cm. above the great annectant Rolandic gyrus. 

 In the anterior direction a shallow tissuret, which might have been the sulcus precentralis margiualis, 

 formed a limit, and posteriorly, diseased cells descended to the floor of the fissure of Rolando. 



Concerning the number of degenerated cells in this area, although a very large percentage of the total 

 showed the reaction, it could not be said that there had been a clean sweep, for while in some sections 

 it could be truly stated that not a single normal cell remained, in others a few isolated members escaped 

 and preserved a perfectly healthy appearance. 



Next when we compared the diseased area with the cell groups which Bevan Lewis and Henry Clarke 

 have described and which I have previously referred to, we were struck by several points of interest. We 

 found that the degeneration was confined to three groups of cell nests, viz. the group on the mesial surface 

 of the hemisphere, the large collection on the convexity close to the upper margin of the hemisphere, and 

 the next small group which lies more or less on the free surface of the convolution ; all these groups had 

 suffered severely, and there was scarcely .1 cell nest to be found in any of them in which one or more 

 members were not affected, in fact, in many nests not a single cell remained healthy. And as to the 



1 It must be mentioned here that while elements showing a similar kind of degeneration were found in the hinder 

 part of the paracentral lobule, these elements differed from Betz cells, the cortex they occupied was not of a motor 

 type, mill, in short, they probably represented sensory termini and will be discussed under the postcentral gyrus. 



