OF DENISON UNIVERSITY. 
51 
though they have no isolated course, but give off side-branches to the 
dotted substance ; (2) ganglion cells with nervous processes which lose 
their individuality and by subdivisions are entirely broken up into slender 
branches, losing themselves in the dotted substance.” 
To sum up all, the logical result of Nansen’s observations could 
not long be evaded, and he boldly announces the belief that all gang- 
lion cells are merely nutritive, or may possibly be also seats of memory 
apparently regarding those functions as closely allied ! All really ner- 
vous functions proper, on the other hand are referred to the “intri- 
cate web or plaiting of nerve-tubes and fiibrillse in the dotted sub- 
stance.” Perhaps this is the result to be expected from two implicit 
reliance upon the method of metallic impregnation. 
Without spending more time in the discussion of these theoretical 
considerations we may now pass to the study of our sections, and in 
the present paper confine ourselves to the description of observed 
structures, reserving their discussion for a subsequent occasion. It, 
therefore, what follows resembles too closely a bare description of 
plates, we trust it may serve to prepare for subsequent comparisons. 
External form and measurements. 
That portion of the brain in front of the bridge is ob-pyriform, the 
olfactory lobes corresponding to the stalks of the pear. These lobes 
protrude 9-10 mm. beyond the hemispheres and are attached to their 
crura by an oblique plane looking dorsad and caudad as well as laterad. 
The crura are about 5 mm. wide at the attachment and widen caudad 
to become continuous with the pyriform lobes and, from hemispherical 
prominences, sink to slight elevations whose surface is excavated by 
vessels from the circle of Willis, which cross transversely about 13 
mm. from the front. Immediately caudad to this depression the pyri- 
form lobe springs ventrad as a strong protuberance. A well defined 
white band on the ventro-lateral exposure of the crural expansion in- 
dicates the position of one of the external olfactory tracts, which passes 
parallel to the rhinalis fissure and plunges into the pyriform lobe near 
the middle of its cephalad portion. A smaller band lies nearer the 
median line. The greatest ventral projection of the pyriform lobe is 
opposite the infundibulum and it is the posterior free margin of the 
lobe which constitutes the hippocampus, to the inversion of which the 
protuberance is due. The chiasm lies about 10 mm. back of the ante- 
rior margin of the hemispheres and there seems to be a small band of the 
