605 
1907-8.] Middle Cells of Grey Matter of Spinal Cord. 
Clarke’s column, the post-central cells are often crowded into the form of a 
band on the outer aspect of Clarke’s column. 
D 7. — See fig. 6. — Middle cells appear to be relatively, though not 
absolutely, abundant in this segment. In appearance, they are practically 
indistinguishable from apical group cells of the intermedio-lateral tract. 
The post-central cells, which may extend to quite behind Clarke’s column, 
or into the formatio reticularis in the absence of the reticular group cells, 
are frequently of the smaller, more rounded type. 
D & — Similar to D 7. Cells moderately abundant, and with all the 
usual characteristics — erratic, irregular distribution, scattered thickly or 
thinly, or aggregated into loose groups in any of the possible sites. 
D 7 — 438 L ( x 40 ). 
a. Interaiedio-lateral tract — a few cells only. 
b. Large post-central middle cells. 
b ' . Small post-central middle cells. 
c. Scattered middle cells in anterior and central areas. 
cl. Small cells behind and to inner side of Clarke’s column. 
e. Clarke’s column. 
D 9. — As before. The post-central cells, though sometimes of medium 
size and definite polygonal shape, are, more than in any other segment, 
mainly of the small, rounded type. 
D 10. — In the lower part of the segment the cells are increasing some- 
what both in number and size. The post-central cells (in contrast to D 9) 
tend to be large, and are often hard to distinguish from the reticular 
group, which is not very sharply circumscribed on its inner aspect. 
D 11. — Anterior and central cells more numerous, either scattered or in 
small groups, very similar individually to cells of the apical group, although 
the anterior ones are sometimes more elongated. The post-central cells may 
