e organ of attention to life.
Should it become deranged, however slightly, the mind is no longer
fitted to the circumstances; it wanders, dreams. Many forms of
mental alienation are nothing else. But from this it results that
one of the _roles_ of the brain is to limit the vision of the
mind, to render its action more efficacious. This is what we
observe in regard to the memory, where the _role_ of the brain is
to mask the useless part of our past in order to allow only the
useful remembrances to appear. Certain useless recollections, or
dream remembrances, manage nevertheless to appear also, and to form
a vague fringe around the distinct recollections. It would not be
at all surprising if perceptions of the organs of our senses,
useful perceptions, were the result of a selection or of a
canalization worked by the organs of our senses in the interest of
our action, but that there should yet be around those perceptions a
fringe of vague perceptions, capable of becoming more distinct in
extraordinary, abnormal cases. Those would be precisely the cases
with which psychical research would deal.

This conception of mental action forms, as will be seen, the foundation
of the theory of dreams which Professor Bergson first presented in a
lecture before the _Institut psychologique_, March 26, 1901. It was
published in the _Revue scientifique_ of June 8, 1901. An English
translation, revised by the author and printed in _The Independent_ of
October 23 and 30, 1913, here appears for the first time in book form.

In this essay Professor Bergson made several contributions to our
knowledge of dreams. He showed, in the first place, that dreaming is not
so unlike the ordinary process of perception as had been hitherto
supposed. Both use sense impressions as crude material to be molded and
defined by the aid of memory images. Here, too, he set forth the idea,
which he, so far as I know, was the first to formulate, that sleep is a
state of disinterestedness, a theory which has since been adopted by
several psychologists. In this address, also, was brought into
consideration for the first time the idea that the self may go through
different degrees of tension--a theory referred to in his _Matter and
Memory_.

Its chief interest for the general reader will, however, lie in the
explanation it gives him of the cause of some of his familiar dreams. He
ma