88 The Post central Gyrtt* in Tabc* Dormlis [CHAP. 



DISTRIBUTION OF THE CHANGES. 



We now come to the general distribution of the affected cortex, and as it is essential that this should 

 be plainly indicated, I give, in Plate IX, a plan of the hemisphere and outlines of a number of the sections, 

 with the exact position of the diseased cortex shown by crosses. From which it will be seen that, on the 

 mesial surface of the hemisphere, the area was confined to the cortex lying immediately behind the tail of 

 the Rolandic fissure. (The Betz cells seen to perfection and in great numbers in the sections of the mesial 

 surface were perfectly healthy.) The diagram further shows how in passing down the lateral surface the 

 afl'ected field was limited to the Rolandic wall and lip of the postcentral gyrus, but I must here mention 

 that the area could not be described as a continuous and uninterrupted strip of diseased cortex. Because 

 more or less healthy patches running through two to three sections were come across here and there, and 

 occasionally, even in an individual section, one saw an isolated healthy spot in the midst of the diseased 

 field ; these healthy islets, I take it, corresponded with healthy spinal nerve roots, and seemed to be more 

 numerous in the lower than in the upper extent of the area ; but the laborious nature of the task prevented 

 me from working out their position iu detail, and although it would have been interesting to have done so it 

 is sufficient in the meantime to have shown that the tabic cortical degeneration is limited to the main field 

 under consideration. In regard to the lower limit of the diseased area, it may be said that the changes ceased 

 at the lower extremity of the fissure of Rolando and that the cortex of the parietal operculum was healthy. 



Search throughout the remaining parts indicated in the diagram, namely, the precentral region, the 

 posterior half of the gyrus fornicatus, the precuneus and the whole of the parietal lobe, failed to disclose 

 noteworthy change, not even anything pathoguomonic of general paralysis and absolutely no disturbance of cell- 

 lamination on a line with that above-described and which one could attribute to the tabetic process ; and in 

 confirmation of this it may be mentioned, that although Doctor Mott, in his examination of portions of the 

 opposite hemisphere (apparently a piece of the Ascending Parietal Gyrus was not examined for cells, although 

 it was for fibres), saw minor alterations in the superficial layers, a photograph of a portion of a section of 

 the ascending frontal convolution which lie reproduces shows medium-sized pyramidal cells of good shape, 

 arranged in columns and having long and erect apical processes. 



EXAMINATION OF NERVE FIBRES. 



Those who have examined the medulla and pons, even in cases of very severe tabes, will know that it is 

 exceedingly difficult, almost impossible, to trace the sclerosis beyond the posterior column nuclei, and bearing 

 this iu mind we would not expect to find marked changes in the fibre elements at the cortical terminus. 

 However, alterations do occur, although not nearly on a par with those in the nerve cells, and in this case 

 they were as follows. The radiations of Meynert were of average strength but slightly wavy, and they 

 did not stand so erect as in the normal state. As might have been anticipated, considering the severe 

 destruction of the external layer of large pyramidal cells, the line of Baillarger had lost in distinctness ; in 

 fact, this was the most pronounced alteration noticed. The zonal layer and the fine elements in the supra- 

 radiary and interradiary plexus suffered slightly, but the large medullated fibres in the radiary zone, which 

 above all things characterise the postcentral area proper, were present in normal abundance. 



In further reference to the nerve fibre changes, I would mention that Doctor Mott in a " preliminary " 

 examination of portions of the first frontal, ascending frontal and ascending parietal convolutions of the right 

 hemisphere, saw " a considerable degree of atrophy of the tangential and supraradial and interradial fibres, 

 quite as marked as in a case of fairly advanced general paralysis," but I imagine that this only applies to 

 the ascending parietal sections, for in the illustration which he gives (Plate II, page 125) that gyrus is shown 

 to suffer out of proportion to the ascending frontal. 



I might add that I am acquainted with Jendrassik's observations on the occurrence of changes in the 

 cortical nerve fibres in cases of Tabes Dorsalis, but I venture to say that these were different from the 

 changes I have found, in particular I would emphasise the fact that they were not localised. It is admitted 

 by Jendrassik that they were general alterations, of a similar nature to the familiar changes first described 

 by Tuczek in the cortex in cases of General Paralysis; indeed, it is maintained by some, that Jendrassik's 

 cases were ones of Tabo- Paralysis and therefore his findings cannot be held to influence my case. 



