These nightmare images are very frequently purely mechanical: as of falling terribly downwards, or being enclosed in vaults. And such images are pure physical transcripts. The image of falling, of flying, of trying to run and not being able to lift the feet, of having to creep through terribly small passages, these are direct transcripts from the physical phenomena of circulation and digestion. It is the directly transcribed image of the heart which, impeded in its action by the gases of indigestion, is switched out of its established circuit of earth-polarity, and is as if suspended over a void, or plunging into a void: step by step, falling downstairs, maybe, according to the strangulation of the heart beats. The same paralytic inability to lift the feet when one needs to run, in a dream, comes directly from the same impeded action of the heart, which is thrown off its balance by some material obstruction. Now the heart swings left and right in the pure circuit of the earth's polarity. Hinder this swing, force the heart over to the left, by inflation of gas from the stomach or by dead pressure upon the blood and nerves from any obstruction, and you get the sensation of being unable to lift the feet from earth: a gasping sensation. Or force the heart to over-balance towards the right, and you get the sensation of flying or of falling. The heart telegraphs its distress to the mind, and wakes us. The wakeful soul at once begins to deal with the obstruction, which was too much for the mechanical night-circuits. The same holds good of dreams of imprisonment, or of creeping through narrow passages. They are direct transfers from the squeezing of the blood through constricted arteries or heart chambers. Most dreams are stimulated from the blood into the nerves and the nerve-centers. And the heart is the transmission station. For the blood has a unity and a consciousness of its own. It has a deeper, elemental consciousness of the mechanical or material world. In the blood we have the body of our most elemental consciousness, our almost material consciousness. And during sleep this material consciousness transfers itself into the nerves and to the brain. The transfer in wakefulness results in a feeling of pain or discomfort--as when we have indigestion, which is pure blood-discomfort. But in sleep the transfer is made through the dream-images which are mechanical phenomena like mirages. Nightmares which have purely mechanical images may terrify us, give us a great shock, but the shock does not enter our souls. We are surprised, in the morning, to find that the bristling horror of the night seems now just nothing--dwindled to nothing. And this is because what was a purely material obstruction in the physical flow, temporary only, is indeed a nothingness to the living, integral soul. We are subject to such accidents--if we will eat pancakes for supper. And that is the end of it.