424 TRANSACTIONS OF THE CANADIAN INSTITUTE. [Vou VI. 
completely but leaves the diffused substance and the periphery of the 
nucleolus unaffected. 
Stage 5. Adult cell. Differs from stage 4 only in the distribution of 
the chromatin which has diffused into the cytoplasm. 
II.—ON THE STRUCTURE OF THE NERVE CELLS IN OTHER 
CLASSES OF ANIMALS. 
When such a remarkable change as that described in the development 
of the Nissl granules occurs in mammals and birds, one would expect to 
find some trace of it in the nerve cells of other animals. With this in 
view the nerve cells of adult animals of the different classes were 
examined. Before giving the results it would be advisable to make as 
complete a list as possible of those forms in whose nerve cells a sub- 
stance analogous to that of the Nissl granules has been found. The 
following authors have dealt with the structure of the nerve cells of dif- 
ferent mammals;—Flemming,” Nissl, Vas Mann, Dogiel,* Held, Eve, v. 
Lenhossek,” Lugaro,* Cajal, van Gehuchten, Cox, Biihler, Heimann, 
Rohde,” Ruzicka and many others. In all cases recorded for mammals 
the nerve cell contained the granules. The only exception to this state- 
ment is that of Reinke who, in the discussion of v. Lenhossek’s paper 
before the Anatomische Gesellschaft, stated that he had found large nerve 
cells in the ganglion of a cat free from granules. In all ganglion cells of 
the cat examined Nissl granules were present, and it is probable the 
cells found by Reinke were in a diseased or otherwise altered ganglion. 
The nerve cells of the animals below mammals have been studied with 
methods that would show the Nissl granules as follows :— 
From Aves: in the pigeon,” raven,” and fowl.” 
54 Flemming, l.c., and Archiv f, Psychiatrie, XXIX, p. 969, 1897. 
55 Mann, Gustav., Journal of Anatomy and Physiology, XXIX, p. 100, 1894. 
56 Dogiel, A. S., Archiv f. Mik, Anatomie, XLI, p. 62, 1893. 
57 v. Lenhossek, M., l.c., also Verhand, der Anat. Gesellschaft, 1896, p. 29. 
58 Lugaro, Rivista di pathologia nerv e, ment., 1896, p. 12. 
59 Cox, W. H., lc. and Anat. Hefte, X, Heft 31, p. 73, 1898. 
60 Rohde, E., ‘‘Die Ganglienzelle,” Zeit. f. Wiss. Zool., LXIV, p. 697, 1898. 
61 Held, l.c. 
62 Bihler, l.c. 
63 Timofeew, l.c. 
