sensations emanating from all points of the organism and,
more particularly, from the viscera. One cannot imagine the degree of
sharpness, of acuity, which may be obtained during sleep by these
interior sensations. They doubtless already exist as well during waking.
But we are then distracted by practical action. We live outside of
ourselves. But sleep makes us retire into ourselves. It happens
frequently that persons subject to laryngitis, amygdalitis, etc., dream
that they are attacked by their affection and experience a disagreeable
tingling on the side of their throat. When awakened, they feel nothing
more, and believe it an illusion; but a few hours later the illusion
becomes a reality. There are cited maladies and grave accidents, attacks
of epilepsy, cardiac affections, etc., which have been foreseen and, as
it were, prophesied in dreams. We need not be astonished, then, that
philosophers like Schopenhauer have seen in the dream a reverberation,
in the heart of consciousness, of perturbations emanating from the
sympathetic nervous system; and that psychologists like Schemer have
attributed to each of our organs the power of provoking a
well-determined kind of dream which represents it, as it were,
symbolically; and finally that physicians like Artigues have written
treatises on the semeiological value of dreams, that is to say, the
method of making use of dreams for the diagnosis of certain maladies.
More recently, M. Tissie, of whom we have just spoken, has shown how
specific dreams are connected with affections of the digestive,
respiratory, and circulatory apparatus.

I will summarize what I have just been saying. When we are sleeping
naturally, it is not necessary to believe, as has often been supposed,
that our senses are closed to external sensations. Our senses continue
to be active. They act, it is true, with less precision, but in
compensation they embrace a host of "subjective" impressions which pass
unperceived when we are awake--for then we live in a world of
perceptions common to all men--and which reappear in sleep, when we live
only for ourselves. Thus our faculty of sense perception, far from being
narrowed during sleep at all points, is on the contrary extended, at
least in certain directions, in its field of operations. It is true that
it often loses in energy, in _tension_, what it gains in extension. It
brings to us only confused impressions. These impressions are the
materials of our dreams.