698 DR JAMES W. DAWSON ON 



on the outer side it involves the tapetum, the optic radiations, and the inferior longitudinal 

 fasciculus ; and posteriorly it is continued in a series of round or oval areas along the line 

 of these groups of fibres to the apex of the occipital lobe. Around the anterior horns the 

 sclerosis is less extensive, but the ventricular surface of the corpus callosum is affected by 

 a narrow zone, specially marked at the angle of one ventricle. A broad band of diffuse, 

 faint staining is present on the ventricular surface of the right optic thalamus, and within 

 this incomplete sclerosis lie denser areas — especially towards its posterior and outer portion. 

 Two well-defined early areas are found in the retro-lenticular portion of the internal capsule, 

 and narrow bands of demyelinated tissue lie in the claustrum. The optic thalamus on the 

 left side is not so extensively affected, but several small areas lie near its anterior ventricular 

 surface. A number of minute areas occur in the white and grey matter of the different 

 lobes : some of these are limited to the cortical white matter or to the medullary rays, but 

 most extend from the medullary ray into the cortex. The most clearly-defined of these 

 areas lie in the convolutions of the right parietal operculum, and the left middle temporal 

 convolution. 



(2) Horizontal sections through the basal ganglia above the middle of the optic thalamus 

 (figs. 95-96). The peri -ventricular affection around the posterior horns is now still more 

 evident : the lateral walls of the ventricle show broad zones of sclerosis, which on the right 

 side can be traced in the white matter from the retro-lenticular portion of the internal capsule 

 almost to the tip of the occipital lobe. On the left side areas, apparently isolated from 

 this zone, pass outwards almost to the base of several of the medullary rays of the parietal 

 convolutions. The ventricular surface of the splenium of the corpus callosum, on both sides, 

 is eaten through by dumb-bell shaped areas, which pass through the forceps major into 

 the medullary rays of the convolutions of the gyrus fornicatus. The ventricular surface 

 of the central part of the splenium is also extensively involved, and in addition several minute, 

 oval, isolated areas occur in its substance. The long diameter of these areas is in the long 

 axis of the fibres. The anterior horn on each side shows an almost symmetrical involvement, 

 being surrounded by a deep bowl-shaped or cup-shaped area, which in other sections is found 

 to be continued for some distance into the frontal white matter. The ventricular surfaces 

 of the optic thalamus show an early change, and the zone of sclerosis along the lateral wall 

 of the posterior horn is continuous with sclerotic tissue at the posterior border of the medial 

 nucleus. The branches of the lenticulo-optic and lenticulo-striate vessels have dilated 

 adventitial sheaths and are surrounded by lighter-stained zones. One of these, on the left 

 side, extends to involve a part of the optic thalamus, the posterior limb of the internal cap- 

 sule, and a portion of the lenticular nucleus. Numerous minute and larger areas are present 

 in the white matter of the medullary rays, some of which reach over into the cortex. On 

 the left side one of these sharply cuts off the fibres as they pass to two convolutions of 

 the parietal lobe, and completely demyelinate the rays and radiations of these, with the 

 exception of a few radiating fibres of one convolution. 



(3) In the ^hemispheres at all the levels above the roof of the lateral ventricles (fig. 97) 

 a very large number of areas were present. Some of these were large and affected the white 

 matter at the base of several adjoining convolutions, and extended to involve grey and white 

 matter indiscriminately : the cups of several of the convolutions were also involved. The 

 more striking of the areas are well brought out in figs. 97 (a), 279, and 281. 



Case IV. 



Clinical Notes. 



J. W., admitted to Longmorc Hospital, 2nd December 1910; died 17th January 19H- 

 Duration of illness — five years. 



