44G me. J. L. CLAEKE on the GEET StrBST.4NCE OF THE SPINAL COED. 
traversed by this band, and near the level of the canal, may be considered as 
between the anterior and posterior cornua. At tlw border it orms^a 
or less pyramidal projection {F, figs. 2 & 4, Plate . , an gs. o. , , ^ 
which kvery transparent, and in colour resembles the gelatinous suMance. In smum 
parts of the Lrsal region, as we shall presently see, it extends inwards ' ‘ 
conical layer, and becomes less transparent towards the piomt, whic ’ . 
the front of the posterior vesicular column (fig. 3, Plate XXI. , an o- o ' 
Phis tract which I intend to follow through other regions of the cord, was fii'st pom 
t hv mvself in 1851 * I shall call it, on account of its position, the fractus inte,- 
for the most part of oval, fusiform, or pyuiform and tnmi 
lular cdls which are somewhat smaller and of more uniform ‘t®- ®* 
anterior cornu. Figs. 51 and 52, Plate XXII., represent them magnified ..0 diameters. 
In the middle of the dorsal region they are less numerous than in some othei pai s 
d f rmro ly near the verge of the grey substance. They are elongated as well 
Is^^ ely as longitudinally,-f™i™«-^«^^ both in a lateral and antero-posterior diiec- 
oT in hid they send thel- processes, on the one hand, to the transverse comni^sure 
dl’de lateral column, and on the other, to the anterior and posterior cornua, bon e- 
‘times a few lie beyond the border of the grey substance, where their processes acco - 
pany nerve-fibres and blood-vessels which radiate through the lateral column (ng. . a. 
Plate XXII. ; and tig. 2, Plate XX. F). _ 
The outer or lateral portion of the eermx cornu posterioris (Plate Xi . ■ 
corresponding part on the opposite side of the tigure), between 
iato alisandthecayurfcornu, is composed of fibres and cells. I he res escen lom 
the roots of the nerves, and run partly outwards to the lateral cohiniii,_ 
forwards to the anterior cornu, passing through the tmetus u.fennedw-latemhs 1). 
The cells which are often of considerable size, are mostly fiisitorm m the same direction 
t the fibres, and taper into processes of remarkable length, vvliich seem to be con- 
‘tinuous with them. But some of the cells are stellate or irregular in shape, and send 
out their processes in all directions. These are generally observed near the outer horde i 
of the poLrior vesicular column, with which they are partly connected by their pro- 
cesses and near the edge of the cervix and the have of the caind cornu, where some 
their processes contribute with blood-vessels and fibres to fonn a uetwo* iirou.id seve 1 
lontritLinal bundles, with which others are i>robahl,j contiiinous. A N (fig. 2) ai. 
three of these lougitudinal bundles, the most anterior of which is partially einbiacec n 
1 miillolar cell, and the most posterior by another of a crescentic form 1 he on to 
cells of the posterior vesicular column are so gradually intermixed with this lato.al 
layer that it seems almost impossible to determine their exact limits. 
In’ receding from the middle of the dorsal region towards either extremity of the con 
the posterior cornua gradually separate from behind forwards, receiving between them 
th:le"oacliingLers o^the posterior columns, until in the middle of the cervical 
* Philosopliical Ti’auBactious, Piu-t II. p. 613. 
