THE SPINAL COED IN MAN, MAMMALIA, AND BHIDS. 
913 
The anterior grey substance (/, fig. 1) was of a somewhat triangular form, with one 
of its angles behind and the other two in front. The posterior angle, which projected 
a little into the lateral part of the antero-lateral column, consisted of a very distinct 
« and dark group of nuclei, and was separated from the posterior grey substance (V) by a 
much paler structure, composed chiefly of longitudinal and radiating fibres, which 
formed the rudiments of the lateral column. The anterior and outer angle was more 
obtuse (like a right angle rounded 00 “), and consisted also of a distinct and dark, but 
larger group of nuclei, from which the majority of the anterior nerve-roots [g) originated, 
and then proceeded outward and forward, to join the posterior roots which escaped in 
the same direction from the intervertebral ganglion. At its inner side, the triangular 
mass, like the posterior grey substance, was continuous with the layer surrounding the 
central canal by a nucleated network of the same kind. 
Throughout the whole of the posterior grey substance there was no diversity in the 
appearance either of the nuclei or of the close network of fibres by which they were 
connected. In the anterior grey substance, however, there was a slight diversity in the 
appearance of both. The nuclei contained in the separate groups already described 
were not larger, but they ■were less round or oval, or more irregular in shape, than those 
of any other part of the section, either anterior or posterior. They had also some 
tendency to aggregate into small, irregular and imperfectly isolated clusters, which 
were interspersed with granules and united by a looser and also irregular network, so 
that the entire structure had more or less the appearance of a sponge-like arrangement. 
In the central layer surrounding the canal, and of which the inner portion constitutes 
the epithelium, the nucleated network had a radiating tendency, which decreased on 
extending outward. In the parts between the separate groups or masses of grey sub- 
stance, the nuclei were densely but uniformly aggregated, and the network of fibres was 
less distinct. 
The antero-lateral white columns {h) were very small in proportion to the quantity of 
grey substance. Behind, where they joined the posterior columns, they were much 
shallower, and reduced, indeed, to a mere fringe on each side, sunk in the depression 
between the anterior and posterior grey substance, from which they were developed as 
the rudiments of the so-called lateral column. Hitherto the anterior median fissure 
had no existence, but fibres proceeding from the anterior nerve-roots on each side could 
be seen to cross each other transversely in front of the epithelial layer which surrounded 
the canal. These transverse fibres were the rudiments of the anterior commissure. 
Sm’rounding the white columns and enclosing the intervertebral ganglia, there was 
a quantity of loose tissue, which in front formed a deep layer {i), connecting the cord 
with the body of the vertebra [j j), and consisting of a nucleated network, the meshes 
of which were transversely extended. The nuclei of this network, although much 
less numerous than those of the grey substance of the cord, differed from them but 
little in general appearance. Their connecting fibres, however, were thicker, coarser, 
less granular, and directly continuous, at the surface of the anterior commissure, with 
6 I 2 
