632 DR JAMES W. DAWSON ON 



angle of the ventricle to the foot of the calcarine fissure. Several small isolated 

 areas are found in the splenium itself. The anterior cornua of the lateral ventricles 

 also show small patches of sclerosis at their tip, both very small in size however. 

 The remainder of the ventricular surface is unaffected on the left side ; and on the 

 right side three isolated patches are found : a small oval area close to its anterior 

 surface, a narrow band in the middle line, and a larger oval patch on the surface 

 opposite the splenium. These are all related to the ventricular surface of the 

 optic thalamus. 



Basal ganglia. — A small oval area of sclerosis is present in the centre of the left 

 optic thalamus, but the right, except for its ventricular surface, is unaffected. A 

 number of minute areas occur in the anterior and the posterior limbs of both internal 

 capsules, while a larger area is found on the posterior surface of the mesial border 

 of the right putamen. The left putamen contains two early patches. One area, in 

 the right claustrum, extends to involve two of the convolutions of the island of 

 Eeil. In the left claustrum there are six small round or oval areas, each of which 

 extends into the white matter on each side, and one reaches as far as the putamen. 



Convolutions. — The left frontal lobe appears normal with the exception of one 

 strongly-marked oval area in the medullary ray and grey matter of the anterior part 

 of the frontal operculum. An equally well-marked area is found at the posterior 

 part of the calcarine region — extending from white matter directly to the surface. 

 In the right hemisphere small areas occur in the white matter of the frontal lobe ; 

 a slightly larger one is present towards its anterior margin, extending into the 

 medullary ray and grey matter of the gyrus. Two minute early areas are present in 

 the middle of the white matter of the frontal operculum, and a number of narrow, 

 irregular areas — some extending for a distance of over a centimetre — are found 

 limited to the cortical grey matter of this operculum, both on its outer and inner 

 aspects, and on the surface of the island of Reil itself. Similar patches occur in the 

 greater part of the parietal region, together with a large number of minute patches 

 and one larger one at the junction of the white and grey matter in the cuneus. In 

 the occipital lobe, a large number of minute patches, at all stages of development, are 

 present both in the white and grey matter. These are grouped mostly towards the 

 mesial surface and especially around the calcarine fissure. A few early areas occur 

 also extending posteriorly from the peri-ventricular area already described. 



(2) At the level of the roof of the lateral ventricle (fig. 26). 



The most striking feature at this level is the large irregular area occupying 

 the whole of the outer wall and posterior tip of the ventricle. This sclerosis 

 extends irregularly into the adjacent white matter and completely cuts across the 

 superior longitudinal fasciculus. A number of isolated areas, in different stages of 

 development, are found along the mesial wall of the ventricle : these extend into the 

 corpus callosum. Several large round and oval well-defined areas are found in the 



