628 DR JAMES W. DAWSON ON 



crossed pyramidal tract, the posterior horn, and the adjoining fibres of the column 

 of Burdach ; the other on the left side, extending lateralwards from the anterior horn. 

 In the fifth segment there is one small oval patch in the region of the septo-marginal 

 tract, and in the next segment two small patches appear, one in the centre of the 

 left crossed pyramidal tract and the other towards the outer part of the column of 

 Burdach. Still lower the whole of the anterior and antero-lateral columns with the 

 anterior horn are completely sclerosed, with the exception of a few fibres along the 

 direct cerebellar tract. In the eighth segment the sclerosis, which forms a quadri- 

 lateral around the central canal, involves each anterior horn completely and the 

 anterior fourth of the posterior columns. At the junction of DlO and Dll there is 

 a complete transection of the cord, except a few fibres along the outer border of 

 the anterior columns. 



Lumbar region (figs. 59-60). — At the level of the second segment one lateral 

 patch involves the crossed pyramidal and ascending cerebellar tracts ; in L 3 this 

 area shows an early "shadow" sclerosis, and another patch, circular, around the 

 central canal, extends forwards along both sides of the anterior median fissure. 

 Here also the sclerotic tissue shows a marked symmetry, which is slightly masked by 

 the shadow sclerosis in the lateral region. At the junction of L4 and L5, both these 

 areas are normal and three other, isolated, patches are present — one in the left 

 antero-lateral column, one in the right lateral column, and one along the two sides 

 of the posterior fissure. 



Sacral region (figs. 61-63). — In the upper part one small patch passes forwards 

 from the tip of the anterior horn to the periphery, and on the left side three smaller 

 areas are present related to lateral vessels. At the third segment one large area 

 involves almost the whole of one side of the cord, with the exception of a small 

 portion near the median line. This area increases as we pass downwards, until it 

 involves the whole of the lower sacral region and conus. The nerve roots of the 

 cauda are normal. 



Medulla Oblongata. 



Just above the decussation of the pyramids one small patch is found at the tip of 

 the right substantia gelatinosa Rolandi — a patch which increases in size as it is traced 

 upwards, when a symmetrical area develops on the opposite side (fig. 32). At the 

 level of the middle of the inferior olive (fig. 35) there is a large area in the interior of 

 the left olive and a second smaller area at the margin of the opposite restiform body. 

 Still higher, these patches become larger and more prominent, and involve almost 

 the whole of one inferior olive and extend from it along the side of the medulla to 

 the restiform body, which is also sclerosed. The opposite olive and restiform body 

 also show small areas (fig. 36), and another small triangular area is present between 

 these structures, in the position of the tract of Gowers. 



At the upper level of the medulla (fig. 38) both lateral margins are involved by 



