evidence for or against this belief. Barry et al. ( 14 ) have made a
study of suggestibility to postural sway suggestions in the "normal
state," the "relaxed state," and in the "daydream state." They found
evidence that these three states have some influence on suggestibility,
the daydream and relaxed states being most alike in this respect and
the waking and relaxed states the least alike. Unfortunately they do
not report in what direction these influences were, so that the above
belief remains unsubstantiated.

To terminate this discussion, we might mention a number of reports
concerning the influence of hyperventilation on suggestibility. Cohen
and Cobb ( 72 ) found some indication that hyperventilation increases
susceptibility to hypnosis. This had been suggested at an earlier date
by Stockert ( 430 ). Sargant and Fraser ( 389 ) reported the same for
neurotic individuals. This was confirmed by Talbot et al. ( 438 ) and
by Seeligmuller ( 408 ). Since hyperventilation leads to alkalosis, it
can be considered in this respect as a pharmacodynamical agent. How
this influence comes about is still to be determined. It should be noted
that the above holds primarily for hypnosis, or rather its induction,
and can be said to apply to waking suggestibility only indirectly
through the latter.

It may be well to summarize briefly the main results examined in
this chapter, inasmuch as the numerous facets of the problem of
heightened suggestibility tend to be confusing. In general, it has been
seen that primary suggestibility can be increased through homoaction,
that is, through the repetition of the same suggestion, provided the
subject responds to some extent, however small, to the first statement
of the suggestion. This appears to be a consequence of the fact that
response to a suggestion tends to facilitate response to a repetition of
this suggestion. This facilitation persists over a period of time,
although it gradually decays. When repeated similar suggestions are
given with sufficient rapidity, the suggestibility for the same progres-
sively increases, eventually attaining a limiting value. The trend that
this increase follows is similar to that followed by habituation. This
homoaction is found to be the same in properties and magnitude in
both waking and hypnosis. Furthermore, homoaction produced in one
state tends to persevere into the other. Although homoaction is also
found in secondary and tertiary suggestibility, its properties are less
well defined, and its magnitude is definitely smaller. Except in con-

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