THE HISTOLOGY OF DISSEMINATED SCLEROSIS. 713 



markedly widened. In C7 the posterior column area has almost disappeared, except for a 

 narrow oval zone along the median fissure. An irregular area is present in the anterior 

 half of the cord ; this forms a square arranged along each side of the anterior fissure, with 

 the posterior commissure as its limit. Irregularly-shaped dense areas also occur near the 

 tip of each posterior horn : an oval area, larger on one side, in each antero-lateral column ; 

 and a small area picks out the centre of the postero-lateral group of nerve cells in the anterior 

 horn. The same widening of the glia border zone is again present.- At the lower level of 

 this segment the areas tend to fuse : the antero-lateral column on one side is occupied by 

 a large triangular patch which leaves the fibres of the direct cerebellar tract untouched 

 and is continuous, across the grey matter, with the anterior quadrilateral patch. A small 

 isolated area is also present in the tip of the anterior group of nerve cells on this side, and 

 two other areas, irregularly triangular, with base to the pia, are present in the lateral 

 column of the opposite side. The area in the posterior columns is much larger and forms 

 an elongated oval reaching almost from posterior commissure to surface. At C8 one-half 

 of the cord is normal, with the exception of a narrow band which picks out the tip of the 

 posterior horn. A portion of the column of Goll also is affected as part of the extension 

 across the median fissure of a square area which occupies almost the whole of the opposite 

 posterior columns. The whole antero-lateral portion of the cord on this side is affected — 

 both grey and white matter, but in this sclerotic tissue bands of myelinated fibres stand 

 out clearly — these roughly correspond to the emerging anterior root fibres with the inter- 

 mediate tissue and to a zone of fibres occupying the extreme lateral periphery of the cord. 



Dorsal Region (figs. 189-193). — In the first segment an area is present in the posterior 

 columns : this occupies its mesial and one lateral portion, and its mesial border, parallel to 

 the median fissure, is clearly defined from the posterior commissure to the periphery. 

 Small surface bands of sclerosis are also found at the posterior root-entry zones on each side, 

 and the rest of the fibres over almost the whole transverse section stain more diffusely and 

 lightly than in the normal cord. In the mid-dorsal region the section is normal, except 

 for a small area which extends inwards from the antero-lateral surface of the cord on one 

 side and small areas at the tips of the posterior horns. In the lower dorsal region a trian- 

 gular area again occupies almost the whole of the posterior columns, leaving symmetrical 

 bands of fibres adjoining the posterior horns. The blunted apex of this triangle reaches 

 as far forwards as the base of the anterior fissure.' As this area is traced downwards it 

 graduaUy diminishes in size, and in the upper part of D12 is present as a broad band, on 

 the posterior periphery, which sends a narrow process forwards along each side of the median 

 fissure : the whole of the rest of the posterior columns shows an early change. At the lower 

 part of this segment the picture is again altered ; a dense area of sclerosis follows the line 

 of one para-median vessel, and an early change involves the rest of the posterior columns 

 and part of the lateral and anterior columns. 



Lumbar Region (figs. 194-199). — At the upper level of this segment a peri-central sclerosis 

 extends into each crescent, and the posterior median fissure is the central point of a narrow 

 oval area. At the lower part of the second segment several minute areas occur : the peri- 

 central sclerosis extends further into one crescent : in the opposite grey matter the antero- 

 lateral group of nerve cells is involved : on the same side a narrow zone of sclerosis extends 

 round the surface of the cord with the tip of the posterior horn as its centre, and a minute 

 area is present immediately on one side of the posterior median fissure. In L3 an irregular 

 area, with oblique borders, extends across the dorsal portion of the postero-median fissure 

 — as this is traced downwards it diminishes rapidly and forms a small oval area immediately 

 in the middle fine. Minute areas are also present in each antero-lateral corner of grey 

 matter, and the peri-central sclerosis extends into each crescent. In L4 a dense broad band 

 passes along each side of the anterior fissure, and at its base these unite and expand into a 

 large peri-central area, which extends into one anterior horn. At L5 the whole of this 



