NERVE-CELLS IN THE MAMMALIAN SPINAL-CORD. 
41 
Out-lying Cell. 
Clarke’s Cell. 
74 
68 
68 
79 
65 
72 
60 
68 
76 
69 
61 
63 
61 
77 
59 
73 
55 
61 
63 
55 
One specimen, at level of 1st lumbar nerve-root 
55 55 55 5 ’ 
55 55 55 55 55 • • • • 
„ ,, between 1st lumbar and 12th thoracic nerve-roots 
55 55 55 55 5 « 55 55 
,, ,, at level of 12th thoracic nerve-root .. 
between 12th and 11th thoracic nerve-roots . 
at level of 8th thoracic nerve-root 
Another point of similarity between these cells and those of Clarke’s column is 
the considerable resistance of both, in comparison with the cells of the ventral cornu, 
to shrinkage and other damage incident during the ordinary hardening processes. 
The out-lying cells are well preserved in ordinary bichromate preparations. The degree 
of depth of tint assumed by them, in haematoxylin preparations, varies in various 
preparations, but not in the same preparation. The differences observable in respect 
to depth of stain between cells of the ventral cornu on the one hand, and, on the 
other, the cells of Clarke’s column, are often extremely striking. When large series 
of specimens are searched through, these differences are seen to be of capricious 
nature, and, I think, of little real significance. Although it will often happen that 
the cells of Clarke’s column, as has been claimed for them by v. Lenhossek* and 
others, become stained more deeply than, and with an apparently different kind of 
sepia tint (in, for instance, “ Weigert ” preparations), to the cells of other groups, 
notably of those of the ventral cornu, yet the reverse is cjuite frequently the case 
even in sections from the same levels of the cord. Without, therefore, laying more 
stress on the fact than the above limitation leaves, it is, perhaps, worthy of note that 
the out-lying cells in the radicular zone are found tinted in the same degree and 
manner as are the cells of the vesicular column. 
Also, as connecting them with Clarke’s column is to be mentioned the peculiar 
distribution of the out-lying cells in the length of the cord. I have not observed 
them lower than the level of exit of the 3rd lumbar nerve-root nor higher than the 
level of the exit of the 5th thoracic. They appear, therefore, best seen where 
Clarke’s column is best developed. And where, as above stated,t the cells of 
Clarke’s column are placed, many of them, at least, with their length in the 
transverse plane of the cord, so are the out-lying cells themselves. This suggests that 
perhaps in upper thoracic and other levels where Clarke’s cells are more segmentally 
distributed and lie parallel with the length of the cord, out-lying ganglion-cells, if 
* ‘ Archiv Mikrosk. Anat.,’ vol. 3.3, 1889. 
t And of. Mott, loc. cit. 
Gr 
MDCCCXC.—B. 
