— i6i — 
stained with carmine or hæmatoxylin •) (Heidenhains hæmatoxylin- 
staining can especially be recommended). Fig. loi will probably 
give a good impression of in what multitudes they occur in the 
white substance. 
The processes of the neuroglia cells do not anastomose, 
neither those from the same cells, nor those from different cells. 
Though I have, for instance, seen so many processes issuing close 
to each other as is illustrated in hg. loS^) yet I have not found a 
single anastomosis. In sections, stained, for instance, with Heiden- 
HAIN's hæmatoxylin (fig. loi), it is seen, as, above mentioned, that there, 
between the longitudinal nerve-tubes of the white substance, runs a 
multitude of slender fibres in every direction, but neither, here, are 
anastomoses foimd. The chief part of these fibres, running between 
the nerve-tubes, are neuroglia fibres coming from the neuroglia cells 
and penetrating to the periphery, but some of them are, also, as 
we have seen, branches of protoplasmic processes coming from the 
ganglion cells, and finally some fibres are branches from the nervous 
processes. It is, generally, in sections, stained in the common way 
(i. e. carmine, hæmatoxylin etc), exceedingly difficult to draw any 
distinction between these various kinds of fibres or tubes. 
The cells of the epithelium surr ounding the central 
can al resemble, in their appearance, very much, the neuroglia cells, 
their nuclei have, to some extent, the form and appearance of common 
neuroglia nuclei. At their exterior extremities, these cells have pro- 
cesses which penetrate, at all events to a great extent, to the periphery 
of the spinal cord on the dorsal side, as well as on the ventral one 
(vide fig. 93, 9S, 103); these processes are, consequently, quite like 
those of the neuroglia cells. Some processes from these cells have a 
more lateral direction into the grey substance (vide fig. 94, cec; 102, pec) 
I have not been able to trace these processes to their extremitie .3) 
Vide what is said of that p. 152. 
^) In this preparation I think it is probable that some cells have been stained 
at one and same time and have acquired an appearance as if they were one cell. 
The illustration is drawn to nature as exactly as possible, and it may be seen that 
there are several irregularities in the staining of the mesial part. Similar prepara- 
tions are very often obtained, 
^) In the spinal cord of higher fishes (Teleostii), I have also by chromo-silver 
staining been able to trace the processes of the epithelial cells of the ventral canal 
through the white substance and just to its periphery where they terminate or unite 
with the sheath. As regards the processes of these central epithelial cells in higher 
Vertebrata I will refer the reader to GolgPs observations (^SuUa fina etc, vide list of 
Literature 1885) he has in the spinal cord of the chicken observed similar processes 
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