bal 
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1898-99.] STRUCTURE, MICRO-CHEMISTRY AND DEVELOPMENT OF NERVE CELLS. 433 
cells, but that it gives entirely artificial appearances in the cytoplasm of 
the cells. 
The true structure of the cytoplasm of nerve cells has been the object 
of much investigation by Flemming, v. Lenhossek, Dogiel, Held, Lugaro, 
Cajal, Marinesco, van Gehuchten, Cox, and many others, in fact, nearly 
all the works mentioned contain references to it, and there are good 
reviews of the literature in van Gehuchten, and in Goldscheider*® and 
Flatau. The question is whether there are independent fibrillz, or 
fibrilla forming a reticulum in the cell, or whether the cytoplasm has a 
foam-like structure. 
In this paper I do not intend to discuss the structure of the cytoplasm 
but shall point out, that since the substance of the Niss] granules does 
not diffuse into the cell body before the structure of the cytoplasm is 
determined, (in other words, these are superadded to the cytoplasm), 
they cannot be a part of the fibrillae or reticulum. Thus the Nissl gran- 
ules are not thickenings of the protoplasmic fibrillz, or are not the nodal 
points of the cytoplasmic reticulum, but are independent of the cytoplas- 
mic structure ; and although the fibrille, if they exist, might even run 
through the granules, they would never lose their independence. Several 
of the above-mentioned authors have reached the same conclusion, but 
could give no definite proof of its truth. 
No definite conclusion has been reached as to whether the nucleus 
keeps sending new material from the nucleolus to the cytoplasm, 
during the life of the cell. If it does give out new material to the cyto- 
plasm it certainly does not do so in the manner described by Rohde. 
The latter has described the migration of the accessory nucleoli into the 
cell body to become the Nissl granules, and the migration of the ordi- 
nary nucleoli to become the nuclei of neuroglia cells. He used iodine 
green and fuchsin as stains, and found the accessory nucleoli (which are 
only masses of oxyphile substance) resembled in their staining power 
the Nissl granules. Iodine green and fuchsin form a difficult combination 
to differentiate exactly, and the two appearances described by Rohde* 
can be obtained by a little longer or shorter differentiation ; in any case, 
the resemblance of the staining properties of the oxyphile nuclear sub- 
stance to the Nissl granules is much better seen by using Flemming’s 
orange method (vide ante). Rohde says that by staining with iron-alum 
hematoxylin and long differentiation, the accessory nucleoli retain the 
stain longer than any other part, and thus the process of migration of 
86 Goldscheider und Flatau, ‘‘ Anatomie der Nervenzellen,” Berlin, 1808. 
87 L.c., p. 705. 
