The Astral body in which man functions during sleep is very subtle matter. It resembles the physical. In fact, it is an exact reproduction of it, but it can only be seen by clairvoyant vision. When a man leaves his body in sleep or death, the spirit must leave the physical body before it will be rested and recuperated to enable it to undergo the strenuous daily toil of physical life. Here is an example. Let a man go to bed say ten o'clock. Let him sleep until six next morning. The ordinary man will awaken feeling refreshed and ready for his daily toil. Let him go to bed at ten, lie awake all night, next morning he will not feel refreshed and during the day he may feel sluggish and sleepy. Let him go to bed and lie awake night after night for a few weeks, what will be the result? He will be a physical wreck. Although he may have the same amount of hours lying in bed, he will not feel recuperated and refreshed unless he has had his natural sleep and this can only come to pass. When the soul or spirit withdraws from the physical body, the physical body is not the man, and as long as our materialistic writers who endeavor to interpret dreams fail to grasp the nature of the inner man, the real self, they will be forever groping in the dark. The first question that naturally arises in the mind of the layman is this: How can a man leave his body in sleep and continue its natural functions such as digestion, circulation of blood, etc. We do not consciously direct the circulation of the blood, or any of the natural bodily functions during our waking state. These things go on whether we will them or not. Although the spirit leaves the body in sleep as previously stated, there is still a magnetic connection with soul and body. This magnetic connection acts on the sympathetic nervous system and the cerebro spinal which controls the functions of the human organism. In sleep the astral man may be in the immediate vicinity of his sleeping recuperating physical body or it may be thousands of miles away in space, the magnetic connection still exists regardless of the distance. No matter what distance the astral man is away from his physical body, he can return to it with the rapidity of thought, as the saying is, for it is the soul that thinks, the brain is only an instrument of the soul.