brought about by consciousness. But we are aware that this refinement is seldom completely successful even in the most normal psychic life and that our thoughts ever remain accessible to falsification through the interference of the principle of pain.

This, however, is not the breach in the functional efficiency of our psychic apparatus through which the thoughts forming the material of the secondary mental work are enabled to make their way into the primary psychic process — with which formula we may now describe the work leading to the dream and to the hysterical symptoms. This case of insufficiency results from the union of the two factors from the history of our evolution; one of which belongs solely to the psychic apparatus and has exerted a determining influence on the relation of the two systems, while the