sinuous shadows on the wall, the presence of any entoptic phe-
nomenon may touch off both explicit and implicit types of reac-
tion. We shall return to the fact again and again that visual
reactions may become short-circuited into word reactions. The
patient blind from birth can describe in appropriate words all
of the beauties of the setting sun. Provided such a person were
in the throes of delirium tremens and there were conditional
emotional reflexes of a proper kind present, there is some reason
to think that he might exhibit many of the characteristics of one
suffering from visual hallucination. We have no such factual
case at hand, be it said. This explanation would hold perfectly
well for the asserted cases of hallucinations appearing in patients
long after both eye-balls have been removed.

General Summary. --In considering, as has been done in this
chapter, the various factors which must be taken into account in
providing stimuli for the control of human action, it may be
argued that we have not offered to the subjects experimented
upon the same kind of situations they will meet in daily life.
Rarely are they stimulated with pure monochromatic lights, pure
tones, with two olfactory substances which balance or cancel one
another, and only rarely does the environment offer stimuli to
which they make the simple types of reaction that they make in
the laboratory. The laboratory obviously selects its problems and
investigates one phase of them at a time. For this it has been
criticised. The criticism would be justified if the laboratory made
no effort at other times to make good this defect. That this
science does attempt with some success to deal with larger human
problems, total situations and total reactions will appear from
some of the material we later present. Even granting the nar-
rowness of our conclusions in sensory physiology, it is safe to say
that most of the facts we have presented here have been of service
and will continue to be of service to one or another group of
scientists outside of psychology. Findings in sensory physiology
are used by the physiologists themselves, by the neurologists, by
specialists in ear, nose and throat, by the surgeon, by the psychi-
atrist, and in the Army and Navy, as well as in the arts and trades.
To trace their use in these fields is beyond our present aim.

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