Spatial and Time Relations in Dreams

THE letter with regard to so-called `mind-pictures,' printed on page 372 in NATURE of September 11, has greatly interested me because such non-volitional pictures have been very familiar to me from my childhood up. I used frequently to amuse myself by observing them, especially when in bed, just before I went to sleep, but I can bring them on by closing my eyes at almost any time. They are non-volitional in the sense that I do not knowingly control their content. So far as my consciousness is concerned, I am simply in the position of an observer. The pictures are of moving events and include landscapes with persons and animals, buildings, trees, vehicles, etc. I am totally ignorant at any one moment with regard to what may appear on the scene at the next, and the whole thing is as interesting and amusing as if I were observing an actual scene. The fact that I do not amuse myself with these pictures in my adult age as I used to do as a child, I attribute to the fact that they are mentally tiring. Their production must involve some expenditure of energy in the brain in a way of which I am ignorant.