I dreamt that a cold wind was blowing; I tried to turn up my overcoat collar and woke myself up. Carl Dreher has devised an apparatus which can be set to throw flashes of light at a given time during the night and then wakes him up by means of a buzzer. The flashes have translated themselves in many cases into interesting visions: In one dream the last picture seen before the alarm went off was that of a building in front of which stood very white marble columns standing on a background of intense black. On another occasion extremely bright green snakes hung from trees, the space between the snakes being very dark. On another occasion he was talking to a girl who declares herself to be "intermittently in love." In another dream, he saw himself operating a moving picture machine which threw flashes on the screen regardless of whether he opened or closed the switch. After many such experiments, he saw his apparatus in a dream and woke up without having been directly affected by the light. In this last dream we have a case of dream insight, the dreamer refusing to pay any attention to a stimulus which has become familiar. This explains the phenomenon of adaptation to stimuli. People whose bedroom is near some source of regular constant noise can sleep in spite of that stimulus for their nervous system no longer translates it into fear; nor has it to interpret it lest it might create fear. Every one of the dreams thus produced artificially were closely related to experiences of the day before and to some of the dreamer's memories and complexes. The dreamer's unconscious was merely stimulated by the light flashes to express itself through images including an allusion to those flashes. In other words, the physical stimulus, be it an impression made upon one of the sense organs or an inner secretion, is interpreted by the sleeper according to the ideas which dominate the sleeper's mind at the time, memories of recent experiences or obsessive ideas. Which means that the personality of the dreamer expresses itself through his dreams. We need not heed Pythagoras' warning against eating beans. It is not the stimulus that counts; it is the end result. And the end result seems to depend from the memories which have accumulated in our autonomic nerves. Freud compares the dream work to a promoter who could never carry out his brilliant ideas if he could not draw upon funds accumulated elsewhere (in the unconscious). Silberer says that the appearance of a dream is like the outbreak of a war. There is a popular tendency among the ignorant to attribute a war to some superficial, visible cause, disagreement, insult, invasion. The real causes, however, are much deeper and lie not only in the present but in the past as well. CHAPTER VI: CONVENIENCE DREAMS Some of the hypnogogic visions and experimental dreams I have mentioned contradict the wide-spread belief that sound sleep is untroubled by dreams.