oreconscious activity. But we have not come one step nearer a solution
of the riddle: Why can the unconscious furnish the motive power for the
wish-fulfillment only during sleep? The answer to this question must
throw light on the psychic nature of wishes; and it will be given with
the aid of the diagram of the psychic apparatus.

We do not doubt that even this apparatus attained its present perfection
through a long course of development. Let us attempt to restore it as it
existed in an early phase of its activity. From assumptions, to be
confirmed elsewhere, we know that at first the apparatus strove to keep
as free from excitement as possible, and in its first formation,
therefore, the scheme took the form of a reflex apparatus, which enabled
it promptly to discharge through the motor tracts any sensible stimulus
reaching it from without. But this simple function was disturbed by the
wants of life, which likewise furnish the impulse for the further
development of the apparatus. The wants of life first manifested
themselves to it in the form of the great physical needs. The excitement
aroused by the inner want seeks an outlet in motility, which may be
designated as "inner changes" or as an "expression of the emotions." The
hungry child cries or fidgets helplessly, but its situation remains
unchanged; for the excitation proceeding from an inner want requires,
not a momentary outbreak, but a force working continuously. A change can
occur only if in some way a feeling of gratification is
experienced--which in the case of the child must be through outside
help--in order to remove the inner excitement. An essential constituent
of this experience is the appearance of a certain perception (of food in
our example), the memory picture of which thereafter remains associated
with the memory trace of the excitation of want.

Thanks to the established connection, there results at the next
appearance of this want a psychic feeling which revives the memory
picture of the former perception, and thus recalls the former perception
itself, _i.e._ it actually re-establishes the situation of the first
gratification. We call such a feeling a wish; the reappearance of the
perception constitutes the wish-fulfillment, and the full revival of the
perception by the want excitement constitutes the shortest road to the
wish-fulfillment. We may assume a primitive condition of the psychic
apparatus in which this road is really followed, _i.e._ wher