THE LUMBAR ENLARGEMENT OF THE SPINAL CORD. 953 
terior vesicular columns; b, b, transverse bundles of fibres; c, c, ascending oblique 
bundles, seen in many places passing into the longitudinal bundles; d, d, line marking 
the boundary between cervix and caput cornu, the figure comprising chiefly the cervix. 
Fig 7. Transverse section through part of the posterior cornu of the calf, showing 
the.side of the cornu next the median fissure with the entrance of the posterior roots. 
The figure gives part of the caput cornu immediately adjoining the gelatinous sub- 
stance, with most of the cervix ; a line drawn parallel to the bottom of the paper, 
through B, would about mark the junction between cervix and caput; a, a, boundary 
of the cornu; a’, a’, bundles formed by the posterior roots; B, a large cell, sending 
four of its processes into four different bundles of posterior roots. 
Fig. 8. Longitudinal section completely through the lumbar region of the cord, from 
the calf, the section which is parallel with the median fissure comprising both anterior 
and posterior columns and roots. A, anterior white columns; P, posterior white col- 
umns; the intermediate space representing the gray substance; a, a, a, anterior roots ; 
k, k, looping fibres connecting two different bundles of anterior roots; /, /, descending 
bundles within the gray substance, which seem to be the origin of the fibres, k, E: 
m, m, descending fibres; n, n, ascending fibres; c,c, descending oblique fibres in the 
posterior columns; b, b, ascending oblique fibres; e, e, transverse fibres; e”, descending ` 
bundle, part of which enters the gray substance, another portion continuing a descend- 
ing course within the white column; d, d, looped fibres, forming loops within the gray 
substance (several examples of this are seen along the boundary between gray and 
white substances) ; f, f, bundles which continue in a longitudinal course for a consid- 
erable distance ; p, p, bundles of posterior roots outside the cord; g, g, transverse 
bundles of fibres traversing the substantia gelatinosa ; h, h, longitudinal columns of the 
cornua formed from the transverse bundles g, y; s, bundles which are cut across by 
the plane of section (many such will be seen in various parts of the gray substance); 
the cells are merely sketched, the magnifying power being too low to give any detail 
of their connections with the fibres. "This figure was drawn by the camera lucida with 
eye-piece No. 1, objective 1} inch, giving a power of about thirty diameters. The scale 
is in hundredths of an inch. 
VOL. VIII. 46 
