110 , GEORGE W. BARTELMEZ 
5. Cerebello-tegmental fibers, for the most part to the peri- 
cellular net of the superior ventral dendrite. 
6. Collaterals from the crossed and uncrossed tecto-bulbar 
tracts to both ventral dendrites. 
7. Fibers from the nucleus princeps trigemini to the pericellu- 
lar net of the superior ventral dendrite. 
It is obvious that the chief connections of Mauthner’s cell are 
with the vestibular nerve and its nuclei; most of the other fibers 
come from the acoustico-lateral nuclei, the fasciculus longitudi- 
nalis medialis and the tecto-bulbar system. These fibers and all 
others here described bring data concerning the orientation of the 
animal in space. It should also be noted that the lateral, supe- 
rior ventral and inferior ventral dendrites each have certain dis- 
tinctive fiber connections. 
The internal structure of Mauthner’s cell. Certain cytoplasmic 
characters of this giant cell stand out clearly in ordinary histo- 
logical preparations (i.e., iron hematoxylin after formol-Zenker 
fixation), and the following incomplete description is given in 
the hope that it may serve as a basis for further work. The ac- 
count is incomplete because time was wanting to make the nec- 
essary experiments in technique and there is little doubt but that 
all of the typical cytoplasmic elements described by Cowdry (’12) 
could be studied during various physiological activities. This 
applies to the Miiller cells as well as to Mauthner’s cell, for in 
both cases cells having the same functional connections, in fact, 
identical cells of different individuals could be studied under 
varying conditions. Attention is called to figure 7 in this con- 
nection, for in this brain only Mauthner’s cell and certain of the 
Miiller’s cells showed cytological signs of fatigue. 
Nissl bodies. The chromidial substance is distributed evenly 
through the cell body and bases of the dendrites and is in the 
form of flakes arranged in rows more or less parallel to the surface. 
It appears thus after all the fixations which I have used, viz., 
formol- and formol-osmic-Zenker, Orth’s fluid, strong Flemming, 
and Bensley’s acetic-osmic-bichromate mixture. ‘The Nissl bod- 
ies are relatively small as compared with those of motor cells, 
very numerous (Tagliani to the contrary notwithstanding), irreg- 
