effect. Or such a train of thought may form still other associations, and sink to lower depths of the soul, still to be considered. This upper layer of the unconscious, then, which we find in Freud's theory, is very like the usual sense in which the word "unconscious" is used, especially by those who would see something mental in its activities.
But the unique contribution which Freud has made to the subject is in his theory of the lower layer of the unconscious, which is in many respects totally different in its structure and activities from the upper layer which we have been considering. In order to see his conception more clearly, let us follow for a moment the development of the individual. We all know that the child exhibits many tendencies which in the adult would be signs of criminality, insanity or abnormality. Our conscious personality as it exists to-day is the result of a long process of growth, each stage built on the ruins of the one beneath. The child is savage, primitive; it is only by degrees that he becomes adapted to the restraints of our modern civilization, and represses his old activities. But now, says Freud, such repressed activities leave their traces behind. They may not seem to affect us consciously; we may have even forgotten many of the old ways of thinking and acting, but their traces still exist. What has become of the energy which went to the gratification of our old selfish, individual, feral, modes of thought and action? With most of us the energy has found for the most part new outlets, it has produced the motive force for new developments. It has been "sublimated" to higher uses. But the draining off of the energy from the old modes of action has not been complete. The old primitive tendencies still persist unconsciously in the best of us, and will crop out in some form or other if the provocation be sufficient. We have repressed our childish desires so long that we may have forgotten that they ever existed, but yet they are not quite dead. Particularly is this true in the realm of sex—for Freud holds that the child has a sex life of his own as truly as the adult. It has, to be sure, not yet come to a head in the sexual organs, but it is none the less existent, and in ways which in the adult would be called perversions; which, indeed, if not repressed, are the origin of perversions in later life. Now these old ways of sexual satisfaction are usually repressed under the influence of the environment, yet the tendency to their gratification still exists; we may see it cropping out in the most normal of us in dreams, for example. The energy that went to the satisfaction of such impulses has for the most part been drained off into new channels, but a little of it still remains locked up with the old complexes. Perhaps none of us have as much energy at our disposal for mental work as we ought to have, for some of it still is attached to old and outworn tendencies, making it a little easier and a little more possible for them to come into operation under favoring circumstances than for new tendencies so to do.