302 
ME. J. L. CLAEKE ON THE INTIMATE STEUCTUEE OF THE BEAIN. 
Stilling”*, with this exception, however, that he fell into a still more extraordinary 
blunder than Stilling, by asserting that the longitudinal column is not, as Stilling 
believes, a root of the trigeminus, but “ one of the cut posterior roots of the auditory 
nerve ” (one of the strise medullares) f. It is remarkable that it did not occur to Scheo- 
dee that bundles of fibres so variable in their course and size as the strife medullares 
could not always be found in exactly the same place and present exactly the same ap- 
pearances. Frequently in transverse sections the cut ends of more than one of the striae 
are seen at the surface of the ventricle, and one of these, which is sometimes, but not 
always, situated at the side of the ventricle, was mistaken by Stilling for another root 
of the trigeminus, which he calls its “ inconstant root.” 
(58) Dean’s account of the origin of the facial nerve is by far the fullest and best. 
He states that at the upper part of the nerve, the whole bundle may be traced inwards 
to the longitudinal column, where the central portion of the root terminates abruptly, 
the outer fibres turning off behind and in front of the column, which is thus completely 
encircled by the roots which afterwards pass onwards to the raphe. But “ even,” he 
says, “ in the upper portions of the facial course, where the whole bundle seems at first 
sight traceable to the raphe, the number of bundles actually decussating or passing into 
the raphe seems so small when compared with the great thickness of the root, that I 
am inclined to think that many of the fibres do actually turn downwards, passing down 
in the longitudinal columns on each side of the raphe to the underlying nucleus, justi- 
fying in this respect the conclusion of Stilling. I have been confirmed in this suppo- 
sition, by frequently observing in the columns which Stilling has called the constant 
roots of the trifacial, and Scheodee van dee Kolk roots of the auditory , great numbers 
of fibres obliquely cut across, which are especially noticeable in connexion with the 
abrupt transmission of the facial roots just at this point, and I am inclined to consider 
these columns as, at least, partial channels by means of which the upper portion of the 
facial roots are conveyed downwards, either to the underlying nucleus or to decussate 
below in the raphe” J. 
On the Nuclei and Roots of the Abducens Nerve. 
(59) The roots of the abducens nerve run nearly directly backward, from the junction 
of the anterior pyramid with the lower border of the pons Varolii, to the fasciculus teres 
on the floor of the fourth ventricle, at the same level as the roots of the Kg- A. 
facial nerve. Their course through the pons, however, is slightly undu- 
lating upwards and downwards, describing three gentle curves, as shown 
in the accompanying figure A. As they pass through the pyramid (a) they 
form a single compact bundle, which curves slightly upward. At the back 
of the pyramid, however, this bundle separates into three or four, which 
* Scheodee yah dee Kolk, Medulla Oblongata, pp. 117, 118. f Loc. cit. p. 117 (note). 
X The Grey Substance of the Medulla Oblongata and Trapezium, by John Dean, M.D., Washington, U. S., 
1864, p. 59. 
