262 
and ascending fibres from the inferior regions is not numerous, seldom 
exceeding six or eight, and the form is that of an arborization of the 
nerve twig (Fig. 2). 
On the other hand the terminations upon the collaterals of the 
psychical cells are much more numerous on the final branches, and 
show a very different disposition. The collaterals winding among the 
dendrites of the cells, ofttimes closely applied to them, and twisting in 
and out between the gemmulae, seldom show any definite endings 
until the mid-portion of the layer of small pyramidal cells is reached. 
Then they split up into numbers of exceedingly fine branches, fre- 
quently running parallel with the course pursued by the apical or 
basal dendrites, and eventually give off at frequent intervals ex- 
ceedingly short collaterals, which ordinarily come off from the parent 
stem only on the side toward the nearest dendritic process. Each 
_of the short terminal ramuscules ends in a bulb of precisely similar 
form to those upon the branches of the ascending fibres, that is either 
rounded or biscuit-shaped, and these spherical apparatus are closely 
adjusted against the bulbous tips of the gemmules, at times the 
application being so close as to give the impression of actual contact; 
though it should be remembered that the slightest overlapping will 
produce the same effect, and on the whole it is more probable that 
there is no actual contact, but that the axonal discharges of stimuli 
overleap the infinitesimal distance between bulb and gemmule; there- 
fore the end-bulbs are fixed in their position, and not subject to 
changes resulting from contractile movements of the dendrites, or 
closer or further approximation in any way, except such as may 
result from vascular turgescence or anaemia. 
The interpretation of the function of the terminal apparatus of 
the nerve fibres cannot be made but in one way, namely, that the 
impressions conveyed from external sources to central cell, or from 
local cell to local cell, is not accompanied by a diffusion of the im- 
pulse through the entire cortex, or even at various points along the 
course of the finer branches of the axons, but at single points, per- 
fectly definite in their distribution; and that these points are situated 
only at the extremities of the fibre-twigs in the form of an histo- 
logically exact formation — the bulbous ending of the nerve fibre — 
which in itself constitutes the sole and only means for the carrying 
over of the cellular forces from axon to dendron, and from cell to 
cell; and is in entire conformity with the conception of WALDEYER 
of the entity of the neuron, each cell standing as an unit in the 
nervous formation, and only in contiguity with others at definite points. 
