The earlier psychic state may not have manifested itself for years but nevertheless continues to exist to the extent that it may some day again become the form in which psychic forces express themselves, in fact the only form, as though all subsequent developments had been annulled and made regressive. This extraordinary plasticity of psychic development is not without limits as to its direction; one can describe it as a special capacity for retrograde action or regression, for it sometimes happens that a later and higher stage of development that has been abandoned cannot be attained again. But the primitive conditions can always be reconstructed; the primitive psyche is in the strictest sense indestructible. The so-called mental diseases must make the impression on the layman of mental and psychic life fallen into decay. In reality the destruction concerns only later acquisitions and developments. The nature of mental diseases consists in the return to former states of the affective life and function. An excellent example of the plasticity of the psychic life is the state of sleep, which we all court every night. Since we know how to interpret even the maddest and most confused dreams, we know that every time we go to sleep we throw aside our hard won morality like a garment in order to put it on again in the morning. This laying bare is, of course, harmless, because we are paralyzed and condemned to inactivity by the sleeping state. Only the dream can inform us of the regression of our emotional life to an earlier stage of development. Thus, for instance, it is worthy of note that all our dreams are governed by purely egotistic motives. One of my English friends once presented this theory to a scientific meeting in America, whereupon a lady present made the remark that this might perhaps be true of Austrians, but she ventured to assert for herself and her friends that even in dreams they always felt altruistically. My friend, although himself a member of the English race, was obliged to contradict the lady energetically on the basis of his experience in dream analysis. The noble Americans are just as egotistic in their dreams as the Austrians. The transformation of impulses upon which our cultural adaptability rests can therefore also be permanently or temporarily made regressive. Without doubt the influences of war belong to those forces which can create such regressions; we therefore need not deny cultural adaptibility to all those who at present are acting in such an uncivilized manner, and may expect that the refinement of their impulses will continue in more peaceful times.