718 DR JAMES W. DAWSON ON 



were either in relation to vessels in the periphery of the areas or in narrow zones imme- 

 diately mesial or lateral to the posterior horns. Bielschowsky preparations proved the 

 persistence of a large number of axis cylinders. The ganglion cells were very atrophied, 

 and some were wholly filled with pigment — the jaune degeneration of Charcot. Numerous 

 cells of " fisch " type were present both in the anterior grey matter and in Clark's columns. 

 The central portions of the posterior columns frequently presented a whorl arrangement 

 of the glia, while, on the other hand, the sclerosis of the lateral columns at several levels 

 appeared to be progressing on the basis of an increasing glia hyperplasia. The nerve roots, 

 posterior root ganglia, and membranes presented few changes. 



The areas in the lower medulla (figs. 218-220) were very extensive, but those in the upper 

 medulla and pons (figs. 221-224) were very limited, and were specially related to the angles 

 of the ventricles, the adjoining cerebellar white matter and folia, to the superior cerebellar 

 peduncles, and to the motor and sensory Vth nuclei. 



The peri- ventricular sclerosis of the lateral ventricles was very slight. A very large 

 number of " early " areas were found in the medullary rays of the convolutions, and a few 

 limited to the cortex. The former frequently presented in a striking degree an affection 

 limited to the borders between the white matter and the cortex. Such an involvement 

 could sometimes be traced for a considerable distance along both transition borders of 

 the medullary ray in a narrow convolution, and sometimes along one border, into the cup 

 of the fissure, and along the border of an adjoining convolution. 



Topographical Distribution. 

 i 



Spinal Cord. — Cervical Enlargement (figs. 228-230). — At its upper level the sclerosis 

 affects chiefly the antero -lateral columns and is present in different stages : an early zone 

 is also present along the sides of the posterior-median fissure, while a denser area occupies 

 one posterior horn and extends into the adjacent fibres of the posterior column. At C5 

 one-half of the cord shows a diffuse change, and in the other more normally-staining half 

 there is present a demyelination of the tip of the posterior horn and of the substantia gela- 

 tinosa Rolandi. At C6 the greater part of the cord shows an early involvement, while 

 other areas are present in the lateral columns on one side and in the posterior columns. The 

 more normal fibres are arranged around the grey matter both of the anterior and posterior 

 horns, and in a part of the periphery of the cord. A very similar picture is continued through 

 C7, but as C8 is reached the early extensive involvement of the previous segment gives 

 place, in one lateral column, to a still fainter staining and in the other to a complete 

 demyelination, with the exception of a peripheral zone. Diffuse staining is also found 

 distributed irregularly through the rest of the section : the more normal fibres lie chiefly 

 around the anterior horn, at the base of the anterior median fissure, and in the region 

 of the direct cerebellar tract. The intra-medullary fibres of the anterior root stand out 

 clearly on both sides. 



Dorsal Region (figs. 230-232). — At Dl the condition does not essentially differ from that 

 in the last cervical segments : the dense area in one side is more extensive and the darker 

 staining in the posterior columns is more limited. Throughout the whole of the remaining 

 dorsal region the areas present all show diffuse changes, with a lighter staining of the 

 myelin. The majority of these are found in the posterior and lateral columns, but their 

 outline is very undefined and in no way determined by fibre systems. The fibres along the 

 periphery of the cord and in immediate relation to the grey matter, along all its borders, 

 as a rule stain better than those in the more central parts of the white matter. The grey 

 matter also shows a diffuse staining throughout its whole longitudinal extent : about 

 the level of D6 both anterior horns are obliterated by denser areas, which extend anteriorly 

 to reach the surface at the fissure and lateral siirfaces. They are thus continuous with 



