284 MR. J. L. CLARKE ON THE INTIMATE STRUCTURE OF THE BRAIN. 
of the inferior ends of the olivary body*. On a level with the glossopharyngeal nerve 
it forms a group of considerable size (U, fig. 39, Plate XI.). Its cells are lodged in 
the interspaces between the deep arciform and the longitudinal bundles of fibres already 
described (§ 15), and may frequently be seen to curve round or embrace the latter, 
with which some of their processes are continuous. By this continuity of their processes 
with the longitudinal bundles they probably establish connexions with other cells at dif- 
ferent lengths of the column ; and by a similar continuity with the transverse arciform 
fibres, which freely communicate with each other, and decussate their fellows on the 
opposite half of the medulla, they are brought into connexion with parts on either side. 
In some sections the cells are especially elongated forwards and backwards, as shown at U, 
fig. 39, and send their processes chiefly in both these directions. The processes which 
extend forward, but which are not shown in the figure, sometimes form a kind of 
tapering brush or tail of fibres in connexion with more scattered cells lying along their 
course, and may frequently be seen to communicate with the transverse bundles which 
traverse the grey tubercle (e, fig. 10, Plate VIII.), and the sensory roots of the fifth 
nerve contained therein. By means of a special set of commissural fibres (U', fig. 39, 
Plate XI.), the entire group has a very intimate connexion with other surrounding 
parts, but particularly with the cells on the right of t, belonging to the glossopharyngeal 
nucleus, and with the so-called “ fasciculus teres.” On proceeding from the group 
backward, some of these fibres (at U') turn round at different depths to end in the 
transverse arciform bundles ; some turn round to he continuous with the longitudinal 
bundles ; others pass further backward to the glossopharyngeal nucleus and “ fasciculus 
teres while a few are seen to be continuous with returning fibres of the glossopha- 
ryngeal nerve which do not enter their nucleus. 
(27) Xnl857f I pointed out the fact that the descending portion of the posterior root 
of the fifth nerve, instead of traversing the restiform body, as it was previously believed 
to do, runs down through the front of the grey tubercle, or caput cornu posterioris. 
The transversely cut ends of its longitudinal fibres are represented by the dark spots in 
the grey tubercle at e, fig. 10, Plate VIII. Moreover, I formerly showed^ that both 
the vagus and glossopharyngeal nerve, on their way to their nuclei, traverse the grey 
tubercle and pass through this portion of the fifth nerve ; while I have since had reason 
to think that some of their roots terminate in the grey tubercle as one of their centres 
of origin. 
* Schroder yaw dee Iyolh, who did not recognize this group of cells, says that Stilling has mistaken the 
antero-lateral nucleus for it. This is quite a mistake on the part of Schroder yan dee Kolk, who has him- 
self mistaken the antero-lateral nucleus for what Stilling really means. Stilling was not acquainted with the 
antero-lateral nucleus, which I first pointed out in 1857, and which was subsequently more fully and well de- 
scribed by Dr. John Dean, who gave it that name. The two groups are perfectly distinct, as may he seen in 
fig. 10, Plate YIII., where s is the antero-lateral nucleus, and U the nucleus of the motor root of the fifth 
nerve. 
t “Medulla Oblongata,” read June 1857, Philosophical Transactions, 1858. 
1 Philosophical Transactions, 1858. 
