ON THE SPINAL MARROW. 
131 
than I am to occupy a place at the board of Apothecaries’ or 
Surgeons’ Hall. 
Sir Charles Bell’s important Discovert/ of the Functions of 
the diffet ent Columns . Now, gentlemen, examine once more 
these lateral furrows. Do you find some difficulty in tracing the 
inferior one? You will see on both surfaces at certain°dis- 
tances, and from one end to the other of the canal, little nervous 
fibrils coming out in a line, and then approximating and forming 
a nervous chord. On each surface they proceed from this fur¬ 
row—from the superior surface plainly enough—and, after close 
observation, there can be no doubt that they spring from the 
same furrow on the inferior surface. It is evident, from the 
manner in which they spring from the chord, and from dissection 
of the hardened spinal marrow, that these fibres come from the 
central column above and below. Now, gentlemen, please to 
recollect what has been said of the cerebral nerves of pure sen¬ 
sation and pure motion, and the double root and double function 
of the fifth pair. 
Ihe Manner in which the Spinal Serves arise. —Permit me to 
refer you to, and to recommend to your careful and I am sure 
profitable perusal. Sir Charles Beil’s own account of this, in his 
admirable “ Exposition of the Natural System of the Nerves.” 
The shoit snetch which I am about to attempt will somewhat 
prepare you for that perusal, and will chiefly consist, although 
in other words, of the sum and substance of what he has stated. 
I observe, first, the nerves from the superior surface, and I have 
already seen that that superior surface answers to the portion of 
the brain which gives origin to nerves of sensation: — I trace these 
fibrils from the centre of this surface—I observe that they come 
out as it were bodi/p from the chord, that they approximate, 
unite, and run into and form a ganglion. 1 turn to the inferior 
surface, which more plainly answers to that part of the brain 
whence I traced the origin ot the motor nerves;—I there observe 
these fibrils—they arise from the centre— they are smaller and 
more superficially attached to the chord—they also approximate— 
they unite—they form a nervous chord ■.—they have no ganglion, 
but they join the chord from the superior surface, immediately 
beyond its ganglion, and, as they are penetrating the dura mater, 
and emeiging from that membrane, they coalesce and become 
one nerve. “ Is it then,” inquires the discoverer of the func¬ 
tion of the spinal chord, “ by means of these separate and 
essentially different origins, that the spinal nerve is enabled to 
discharge its apparently double office ?” A less cautious phy¬ 
siologist would have jumped at once to a conclusion. He has 
lecouiseto the infallible test of experiment; and in the conducting 
