1898-99. | STRUCTURE, MICRO-CHEMISTRY AND DEVELOPMENT OF NERVE CELLS. 409 
Nissl"* describes the bodies stained by his method, as having the form 
of larger or smaller, round, oval, spherical, often angular or irregular 
masses which have thread-like processes. These thread-like ‘processes 
often unite the different masses into a true reticulum. Biihler'’’ and 
Cox* for the spinal ganglion cells and Flemming” for the cells of the 
cord of Gadus have noticed this reticulum of chromophilous substance. 
The reticular nature of this substance is frequently seen in the spinal or 
sympathetic ganglion cells, or in the cells of Purkinje in the cerebellum, 
and is occasionally seen in the cells of the cord and cortex. In sections 
stained with toluidin blue alone, the nucleus is seen as a clear space in 
the cell containing a large, round, deeply-stained nucleolus. There is 
usually nothing else stained in the nucleus, but occasionally there may 
be a faint bluish tint along certain lines. 
If instead of employing toluidin blue alone, we use a cytoplasmic 
stain with it, we get the intergranular substance stained as well as the 
granules. The combination of eosin and toluidin blue, as employed by 
Mann, was the one used most frequently, although erythrosin and methy- 
lene blue, as employed by Held, give good results. Using these dyes we 
find the Nissl granules are stained blue, while the intergranular substance 
appears red. (Figs. 1 and 2). The nucleolus is also blue, but the blue 
is not the same as that of the Nissl granules, nor is the blue uniform 
throughout, for in many cases one can see a distinct red centre having a 
blue-stained layer on the outside. (Fig. 21). Probably the greatest 
change the addition of eosin to the stain has made in the appearance of 
the cell is in the nucleus. Here, instead of finding an unstained sub- 
stance, one sees stretching from the nucleolus to the nuclear membrane 
a network of eosin-stained material. This substance is generally 
abundant near the nucleolus and adjacent to the nuclear membrane, 
while extending across the intervening space is a loose network of the 
same material. Sometimes, however, this material is found scattered 
throughout the nucleus ina finely granular form. This eosinophilous 
substance is generally more abundant in the nuclei of spinal and sympa- 
thetic ganglion cells than in the nuclei of cells of the central nervous 
16 Nissl, F., ‘* Mittheilungen zur Anatomie der Nervenzelle,” Allgemeine Zeitschrift fiir Psychiatrie, 
L, p, 372, 1894. 
17 Biihler, lec., p. 98. 
18 Cox, W. H., ‘‘ Die Selbstandigkeit der Fibrillen im Neuron,” Internat. Monat. f. Anat. und, Phys,, 
XV, p. 209, 1898. 
1g Lugaro (Lo sperimentale, 1895), also observed the reticular nature of this substance. Quoted from 
Robertson, Brain, 1899, p. 212. 
20 Flemming, W., ‘ Ueber die Structur centraler Nervenzellen,” Anat. Hefte Heft, XTX, p. 563, 1806. 
(Original inaccessible. Quoted from Bihler). 
