728 DR JAMES W. DAWSON ON 



Fig. 25. Above the left ventricle — numerous areas in the white and grey matter especially. a = in the 

 centre of the white matter towards the frontal lobe ; b = at junction of white and grey matter in the post- 

 Rolandic gyrus; c = area in convolutions of the calcarinc fissure. 



Figs. 27 and 28, x 7. Almost symmetrical involvement of the white matter of the flocculus of the 

 cerebellum — an involvement (a) which extends into the cores of numerous folise. 



Fig. 29. Horizontal section through the temporo-sphenoidal lobe just below the floor of the descending 

 horn of the lateral ventricle, a = extension of the peri-ventricular sclerosis to the region of the calcarine 

 fissure; b = involvement of the convolutions at the tip of the lobe; and c = of the fibres of the 

 hippocampal lobe. 



Figs. 30 and 31, x 2£. Frontal longitudinal sections of the lower cervical cord from serial sections. 

 In fig. 30 note the involvement of the anterior columns on either side of the anterior median fissure, with 

 extension into the grey matter (a) and the lateral white matter (b). Fig. 31, through the central canal, with 

 similar involvement of grey (a) and white (b) matter. Note the indication of the primary oval form 

 of the areas. 



Plate XLIX. 



Figs. 32-47 taken from Weigert serial sections of medulla oblongata and pons. x 2. Note the 

 distribution of the areas in relation to the floor and walls of the IVth ventricle; the involvement of the 

 dentate nucleus ; the frequent sharp definition of the areas ; that several are surrounded by a zone of 

 shadow sclerosis, which has also a sharp outline ; and that nearly all the cranial roots enter into de- 

 myelinated tissue (pp. 628-631). 



Fig. 32. Medulla oblongata above the decussation of the pyramids. 



Fig. 33. At level of accessory olivary nucleus, a = peri-central sclerosis. 



Fig. 34. At lower end of inferior olive. 



Fig. 35. At middle of inferior olive. 



Figs. 36 and 37. At the opening of.the central canal into the IVth ventricle. 



Fig. 38. Upper medulla continuous with the cerebellum, a = entering Vlllth nerve on each side; 

 6 = demyelination of vermis and accompanying nodules. c = involvement of the hilum of the dentate 

 nucleus on both sides. 



Fig. 39. Junction of medulla oblongata and pons. Note involvement of the fibres of the inferior 

 and middle cerebellar peduncles on both sides, with extension to the centre of the corresponding noccuuis. 

 a = figs. 27 and 28 ; 6 = area in the cerebellar white matter. 



Fig. 40. Pons Varolii at the level of the lower third of the middle cerebellar peduncle. 



Fig. 41. Middle of pons. In figs. 38-41 note the involvement of all the cranial nuclei in this region — 

 the nuclei of the Vlth, the cochlear nuclei, and the nuclei of Bechterew and Deiters ; also the complete 

 involvement of both middle cerebellar peduncles. 



Fig. 42. Pons at upper part of the middle peduncle. a = an area in the median raphe, which in 

 higher sections (figs. 43-45) reaches the anterior surface. 



Fig. 43. Upper pons. Note the symmetry of the involvement. 



Fig. 44. Junction of pons and mid-brain, a = area in the middle line which reaches almost to the 

 mesial fillet and cuts across, in sharply-defined lines, the intersecting fibres of the raphe and the adjoining 

 fibres on each side. Cf. fig. 289 and figs. 16, 17, and 421, which show the complete retention of the axi3 

 cylinders across this demyelinated area. 



Fig. 45. Slightly above (fifty serial sections) fig. 44. a = zone of "shadow" sclerosis around area. 



Fig. 46. Fifty serial sections above fig. 45. Note three areas of " shadow " sclerosis, a = in centre of 

 the pyramid ; b = in middle line at level of mesial fillet ; c = at lateral border of mesial fillet. 



Fig. 47. Mid-brain. Aqueduct of Sylvius free, a = area in middle line anterior to the commencing 

 decussation of the superior cerebellar peduncle. 



Plate L. 



Figs. 48-63. Various levels of the spinal cord. Myelin sheath stain, x 2. (Pp. 626-628.) Note 

 that there are few isolated areas and that there is frequent almost complete symmetry of the involvement 



