cinations.

As a proof that the image physiologically assumes the form of a real
appearance, I may mention the experience of myself and others. When
suddenly awakened from a vivid dream I have sometimes, even when I was
fully awake, seen for an instant the figures of my dream still moving,
and projected on the wall. This fact shows that even the images of our
waking state have, in the physiological conditions of the brain, a
tendency to take real forms, so that they may be termed normal, or more
properly, inchoate hallucinations, corrected by the conscious efforts of
our waking state and external consciousness. So that it might be said
that dreams are at first the transformation of our waking thoughts into
normal images and hallucinations, and afterwards into those of dreams,
properly so called.

If the hypnagogic phase actually affects the cerebral cellules in
connection with the various senses of which they are the organs, the
phases of sleep and dreams, strictly so called, have more general
conditions. The idea, converted into an image presented to the senses,
may thus be said to have three stages: that of the waking state, which
depends as we have said on the intensity and vividness with which it is
reproduced, aided by a momentary detachment from the real environment;
secondly, the hypnagogic phase, in which there is the physiological
action of the nervous centres, which produce the image, though still
with the implicit consciousness of the waking state; and finally, the
actual dream, in which this implicit consciousness is almost always
wanting, and the psychical exercise of thought is completely transformed
into visions and figures which are believed to be real. This in its turn
depends upon the other two causes, and on the physiological relaxation
of the body, which is to a great extent isolated, so that the effectual
impulses of external nature are greatly attenuated.

In the waking state, the whole body and all its organs of relation and
movement are in tension. The cerebro-spinal axis virtually excites the
whole muscular and peripheral system in such a way that relaxation or
relative repose becomes impossible. But the brain, with all its
dependencies and appendices, is not only the organ of thought, but it
stimulates and directs our whole system, as numerous experiments have
shown. In the waking state both these functions are exercised equally,
as far as the impulses and functions of the body are concerned,