44 
MR. C. S. SHRERTR-GTON OX OUT-LYING 
coarser fibres of the dorsal nerve-root. In this position Clarke has figured them/"" in 
his fig. 22, PI. XXIV., Phil. Trans., 18.59.t 
The cliief interest attaching to ganglion-cells lying in the white columns is that it 
may well be supposed they are connected with the nerve-fibres among w^hich they are 
placed, and that in this way some knowledge may be gained as to the anatomy of the 
cells themselves, and of the cell-group of which they may be out-lying members, and 
of the fibre-bundles containing them. 
When the out-lying cell is isolated in position, it is not easy to conceive what 
becomes of the branched processes of the cell (Gerlach’s protoplasmic processes). 
The axis-cylinder process, if one exist, may be continuous with a fibre of the adjacent 
fibre-bundle. Are the cells possessed of more than one axis-cylinder process ? Beisso, 
ScHiEFFERDECKER, and Flechsig have at various times urged that cells of such a 
kind exist. In this connection arises a slight difficulty if the out-lying cells of the 
radicular zone are considered individuals belonging to Clarke’s column. In the case 
of the out-lying cells, it is not easy to see that there is evidence of their communicating 
with any representative of the fine-fibred plexus that constitutes so striking a feature 
of the vesicular column itself, and with which it is customary to believe that the cells 
of the column do communicate. 
If the out-lying cells of the dorsal root-zone are, as seems most probable, out-lying 
cells of Clarke’s column, certain suggestions as to the anatomy of that group become 
obvious. These are : that the cells of that group are connected directly with certain 
of the fibres of the mesial division of the sensory or posterior nerve-root, which, 
after an upward course in Burdach’s column, plunge into the grey matter of the base 
of the dorsal cornu : that some, at least, of the cells of the group are interpolated, 
more or less immediately, into the course of medullated nerve-fibres of large calibre : 
that other outstanding individual cells to be reckoned as belonging to the group may 
be present as solitary cells in the near neighbourhood of the substantia gelatinosa of 
the dorsal horn. 
Further, it seems likely that the cells in the root-zone may in the Mammalian cord 
represent the ceils described by Freud^; in the cord of Petromyzon Planeri as 
* From the conus mednllaris of the Ox. 
t They can be seen also in a figure in Van der Kolk. 
J ‘ Sitzungsberichte d. Kais. Akad. zu. Wien,’ vol. 75, III. Abth., 1877, also following year; and 
Lit. Einleitung, No. 12. See also Kutschin, ‘Ueb. d. Ban d. Ruckenm. des Neunanges,’ 1863, abstracted 
in Schultze’s Archiv, 1887, vol. 2 ; also Klausnee on Proteus. [It may be recalled here that Stilling 
(‘Neue Untersuchungen fiber den Ban des Rfickeninarks,’ 1859) suggested that the “grosse runde” 
cells in the spinal cord of Petromyzon, which lie each side of, and dorsal to, the central canal, represent 
in Petromyzon the group of cells described by Clakke in the thoracic region of the Mammalian cord, 
and now generally known as Clarke’s vesicular column. Stilling asserted that these cells in Petromyzon 
possess each a cell-process directly continuous with a nerve-fibre of the dorsal nerve-root. Kutschin, in 
1863 (loc. cit.), confirmed Stilling’s description; he found certain fibres of the dorsal root in Anmo- 
cceies and Petromijzoii directly traceable to the lai’ge cells, which he spoke of as the inner central cell- 
