ntation is lost. Moreover, there are all the conditions present,
both positive and negative, for the hallucinatory transformation of
mental images into percepts just as in natural sleep. Thus, the higher
centres connected with the operations of reflection and reasoning are
thrown _hors de combat_ or, as Dr. Heidenhain has it, "inhibited."

The condition of hypnotism is marked off from that of natural sleep,
first of all, by the fact that the accompanying hallucinations are
wholly due to external suggestion (including the effects of bodily
posture). Dreams may, as we have seen, be very faintly modified by
external influences, but during sleep there is nothing answering to the
perfect control which the operator exercises over the hypnotized
subject. The largest quantity of our "dream-stuff" comes, as we have
seen, from within and not from without the organism. And this fact
accounts for the chief characteristic difference between the natural and
the hypnotic dream. The former is complex, consisting of crowds of
images, and continually changing: the latter is simple, limited, and
persistent. As Braid remarks, the peculiarity of hypnotism is that the
attention is concentrated on a remarkably narrow field of mental images
and ideas. So long as a particular bodily posture is assumed, so long
does the corresponding illusion endure. One result of this, in
connection with that impairing of sensibility already referred to, is
the scope for a curious overriding of sense-impressions by the dominant
illusory percept, a process that we have seen illustrated in the active
sense-illusions of waking life. Thus, if salt water is tasted and the
patient is _told_ that it is beer, he complains that it is sour.

In being thus in a certain rapport, though so limited and unintelligent
a rapport, with the external world, the mind of the hypnotized patient
would appear to be nearer the condition of waking illusion than is the
mind of the dreamer. It must be remembered, however, and this is the
second point of difference between dreaming and hypnotism, that the
hypnotized subject tends _to act out_ his hallucinations. His
quasi-percepts are wont to transform themselves into actions with a
degree of force of which we see no traces in ordinary sleep. Why there
should be this greater activity of the motor organs in the one condition
than in the other, seems to be a point as yet unexplained. All
sense-impressions and percepts are doubtless accompanie