y induce hallucinations by
introducing into the blood other toxic substances, such as Indian hemp
or stramonium. We are not conscious of the mechanism producing the
arterial contraction and the bloodlessness of those convolutions related
to natural sleep. But we are not altogether without control over them.
We can, we know, help to compose ourselves to sleep, as we say in
ordinary language. We retire into a darkened room, we relieve ourselves
from the stimulus of the special senses, we free ourselves from the
influence of noises, of strong light, of powerful colors, or of tactile
impressions. We lie down and endeavor to soothe brain activity by
driving away disturbing thoughts, or, as people sometimes say, 'try to
think of nothing.' And, happily, we generally succeed more or less well.
Some people possess an even more marked control over this mechanism of
sleep. I can generally succeed in putting myself to sleep at any hour of
the day, either in the library chair or in the brougham. This is, so to
speak, a process of self-hypnotization, and I have often practiced it
when going from house to house, when in the midst of a busy practice,
and I sometimes have amused my friends and family by exercising this
faculty, which I do not think it very difficult to acquire. (We also
know that many persons can wake at a fixed hour in the morning by
setting their minds upon it just before going to sleep.) Now, there is
something here which deserves a little further examination, but which it
would take too much time to develop fully at present. Most people know
something of what is meant by reflex action. The nerves which pass from
the various organs to the brain convey with, great rapidity messages to
its various parts, which are answered by reflected waves of impulse. If
the soles of the feet be tickled, contraction of the toes, or
involuntary laughter, will be excited, or perhaps only a shuddering and
skin contraction, known as goose-skin. The irritation of the nerve-end
in the skin has carried a message to the involuntary or voluntary
ganglia of the brain which has responded by reflecting back again nerve
impulses which have contracted the muscles of the feet or skin muscles,
or have given rise to associated ideas and explosion of laughter. In the
same way, if during sleep heat be applied to the soles of the feet,
dreams of walking over hot surfaces--Vesuvius or Fusiyama, or still
hotter places--may be produced, or dreams of adventur