308 



PLATE IX. 



TABES DOHSALIS. 



A series of transverse sections of the central gyri showing the exact distribution of the 

 tabetic cortical changes in Case I. The att'ected part is indicated by crosses and is seen to be 

 almost entirely confined to the posterior Rolandic wall. 



The diagram is further utilised in illustrating the distribution of the giant cells of Betz. 

 In the sectional but not in the surface drawings, each clot represents a cell. Respecting these 

 cells, it is not usual to lincl them so numerous nor so widely distributed on the mesial surface 

 of the hemisphere ; a commoner arrangement is seen in text figure 4. The sudden fall in numerical 

 representation seen in Section 9 and continued in Section 10 is coincident with the appearance 

 of the superior annectant gyrus or buttress. 



The lines of cleavage between the different blocks, and also the extent of the field submitted 

 to examination, are indicated by lines of short rods ; the fine dotted transverse lines show the 

 plane and position of the sections figured. 



