sition of some of the main features of the
localization of function in the _cortex cerebri_, gradually deciphered
by patient inquiry, shows that the scheme of partition of function so
far perceptible does not follow the quaint lines of analysis of the
phrenologists with their supposed mental entities, so-called
"faculties." On the contrary it is based, as some of those who early
favoured a differential arrangement of function in the cerebrum had
surmised, on the _separateness of the incoming channels from peripheral
organs of sense_. These organs fall into groups separate one from
another not only by reason of their spatial differentiation at the
surface and in the thickness of the body, but also because each group
generates sensations which introspection tells us are of a species
unbridgeably separate from those generated by the other groups. Between
sensations of hearing and sensations of sight there is a dissimilarity
across which no intermediate series of sensual phenomena extend. The two
species of sensations are wholly disparate. Similarly there is a total
and impassable gap between sensations of touch and sensations of sight
and sound. In other words the sensations fall into groups which are
wholly disparate and are hence termed species. But within each species
there exist multifold varieties of the specific sensation, e.g.
sensations of red, of yellow, &c. We should expect, therefore, that the
conducting paths from the receptive organs which in their function as
sense-organs yield wholly disparate sensations would in so far as
subserving sensation diverge and pass to separate neural mechanisms.
That these sense-organs should in fact be found to possess in the cortex
of the cerebrum separate fields for their sensual nervous apparatus is,
therefore, in harmony with what would be the _a priori_ supposition.

But, as emphasized at the beginning of this article, the receptive
organs belonging to the surfaces and the depths of the body and forming
the starting-points for the whole system of the afferent nerves, have
two functions more or less separate. One of these functions is to excite
sensations and the other is to excite movements, by reflex action,
especially in glands and muscles. In this latter function, namely the
reflexifacient, all that the receptive organs effect is effected by
means of the efferent nerves. They all have to use the efferent,
especially the motor, nerves of the body. So rich is the connexion