of the roads leading to a knowledge of this structure. If, in addition to our knowledge, we wish to be contented with a minimum perfectly established, we shall say that the dream gives us proof that the _suppressed, material continues to exist even in the normal person and remains capable of psychic activity_. The dream itself is one of the manifestations of this suppressed material; theoretically, this is true in _all_ cases; according to substantial experience it is true in at least a great number of such as most conspicuously display the prominent characteristics of dream life. The suppressed psychic material, which in the waking state has been prevented from expression and cut off from internal perception _by the antagonistic adjustment of the contradictions_, finds ways and means of obtruding itself on consciousness during the night under the domination of the compromise formations. _"Flectere si nequeo superos, Acheronta movebo."_ At any rate the interpretation of dreams is the _via regia_ to a knowledge of the unconscious in the psychic life. In following the analysis of the dream we have made some progress toward an understanding of the composition of this most marvelous and most mysterious of instruments; to be sure, we have not gone very far, but enough of a beginning has been made to allow us to advance from other so-called pathological formations further into the analysis of the unconscious. Disease--at least that which is justly termed functional--is not due to the destruction of this apparatus, and the establishment of new splittings in its interior; it is rather to be explained dynamically through the strengthening and weakening of the components in the play of forces by which so many activities are concealed during the normal function. We have been able to show in another place how the composition of the apparatus from the two systems permits a subtilization even of the normal activity which would be impossible for a single system. [1] _Cf._ the significant observations by J. Bueuer in our _Studies on Hysteria_, 1895, and 2nd ed. 1909.