ME. J. L. CLAEKE ON THE INTIMATE STETTCTXTEE OE THE BE AIN. 
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from which these fibres were derived being now occupied by the beautiful network d' d', 
fig. 28, Plate X., containing in its meshes the longitudinal bundles which are continuous 
with the layer d! n't at the lower border of fig. 27, Plate X. The innermost of these 
bundles (%'), in which the slender column (n) terminates, are, in fig. 28, Plate X., situated 
at the extremity of the line n ; and at this point the lower rootlets of the spinal-accessory 
nerve (r) are connected with the border of the lateral grey substance. Some of the fibres 
of these rootlets turn backward round the little network of fibres (e), mixed with cells., 
joining the lateral grey substance to the grey tubercle or caput cornu posterioris, and seem 
to be connected with it ; while others turn forward toward the remains of the anterior- 
cornu (/')*• Still further down these anterior roots of the spinal-accessory nerve may be 
traced to the anterior horn of the spinal cord, as far forward as the group of cells from 
which the anterior roots of the spinal nerves take their origin, as may be seen in fig. 29, 
Plate X., which represents a transverse section of the grey substance of the spinal cord at 
the lower part of the first cervical nervesf . r indicates three branches of the spinal-acces- 
sory nerve of the left side, proceeding to the lateral grey substance, and thence forward 
to the side of the group of cells in the anterior horn, e is the caput cornu or dilated 
extremity of the posterior horn ; e" indicates the posterior nerve-roots first passing trans- 
versely through the posterior white column immediately behind the caput cornu, and then 
crossing the cervix cornu to the lateral grey substance with which the spinal-accessory 
nerve is connected, and which they separate from the central grey substance (t). At 
the same part of the lateral grey substance we see the origin of some of the decussating 
bundles (f) which form the point or termination of the anterior pyramids, and which 
frequently seem to be continuous with the posterior nerve-roots (e"). The spinal-acces- 
sory nerve appears to be connected with the lateral grey substance all along its border 
from before backward, within the curved line of the lateral column d', into which the 
greater number of the decussating fibres of the pyramids pass (see figs. 2, 3, & 4, Plate 
VIII.). The connexion of the anterior pyramids with this part of the grey substance 
is exceedingly interesting in reference to the influence of the will on the respiratory 
movements. 
(16) The slender longitudinal column n (figs. 25 & 27, Plate X.) has the same kind 
of important connexions with the vagal and glossopharyngeal nuclei as those which it 
has been shown to form with the spinal-accessory ; but it has moreover a direct and 
especial connexion with the glossopharyngeal nerve. While the spinal-accessory and 
vagus nerves enter their nuclei on the inner side of the slender column, although they 
are connected with it, many of the fibres of the glossopharyngeal nerve pass directly into 
it. Fig. 30, Plate X. represents an oblique longitudinal section of the human medulla 
hVthe plane of the glossopharyngeal nerve, and passing through the slender column n n 
and the glossopharyngeal nucleus t". Some of the roots of the nerve (y) are distinctly 
seen to enter the slender column {n) and run with it down the medulla. 
* See my Memoir “ On the Medulla Oblongata,” figs. 19 & 23, Phil. Trans. 1858. 
t See my “ Eurther Eesearcbes on the grey substance of tbe Spinal Cord,” fig. 12, Phil, Trans. 1859. 
