upon the raw material of sensation furnished to
it through the eye, and gives rise to a train of thoughts. First comes
the thought that there is an object at a certain distance; then arises
another thought--the perception of the likeness between the states of
consciousness awakened by this object to those presented by memory,
as, on some former occasion, called up by a hare; this is succeeded
by another thought of the nature of an emotion--namely, the desire
to possess the hare; then follows a longer or shorter train of other
thoughts, which end in a volition and an act--the loosing of the
greyhound from the leash. These several thoughts are the concomitants
of a process which goes on in the nervous system of the man. Unless
the nerve-elements of the retina, of the optic nerve, of the brain, of
the spinal chord, and of the nerves of the arms went through certain
physical changes in due order and correlation, the various states
of consciousness which have been enumerated would not make their
appearance. So that in this, as in all other intellectual operations,
we have to distinguish two sets of successive changes--one in the
physical basis of consciousness, and the other in consciousness
itself; one set which may, and doubtless will, in course of time,
be followed through all their complexities by the anatomist and the
physicist, and one of which only the man himself can have immediate
knowledge.

As it is very necessary to keep up a clear distinction between
these two processes, let the one be called _neurosis_, and the other
_psychosis_. When the gamekeeper was first trained to his work, every
step in the process of neurosis was accompanied by a corresponding
step in that of psychosis, or nearly so. He was conscious of seeing
something, conscious of making sure it was a hare, conscious of
desiring to catch it, and therefore to loose the greyhound at the
right time, conscious of the acts by which he let the dog out of the
leash. But with practice, though the various steps of the neurosis
remain--for otherwise the impression on the retina would not result
in the loosing of the dog--the great majority of the steps of the
psychosis vanish, and the loosing of the dog follows unconsciously, or
as we say, without thinking about it, upon the sight of the hare.
No one will deny that the series of acts which originally intervened
between the sensation and the letting go of the dog were, in the
strictest sense, intellectual and