Vital power is renewed in sleep. Every living thing sleeps; men, animals, reptiles, fish, and insects sleep, and even plants have regular periods of slumber. And this is because it is in sleep that we come into such contact with the Principle of Life in nature that our own lives may be renewed. It is in sleep that the brain of man is recharged with vital energy, and the Principle of Health within him is given new strength. It is of the first importance, then, that we should sleep in a natural, normal, and perfectly healthy manner.

Studying sleep, we note that the breathing is much deeper, and more forcible and rhythmic than in the waking state. Much more air is inspired when asleep than when awake, and this tells us that the Principle of Health requires large quantities of some element in the atmosphere for the process of renewal. If you would surround sleep with natural conditions, then, the first step is to see that you have an unlimited supply of fresh and pure air to breathe. Physicians have found that sleeping in the pure air of out-of-doors is very efficacious in the treatment of pulmonary troubles; and, taken in connection with the Way of Living and Thinking prescribed in this book, you will find that it is just as efficacious in curing every other sort of trouble. Do not take any half-way measures in this matter of securing pure air while you sleep. Ventilate your bedroom thoroughly; so thoroughly that it will be practically the same as sleeping out of doors. Have a door or window open wide; have one open on each side of the room, if possible. If you cannot have a good draught of air across the room, pull the head of your bed close to the open window, so that the air from without may come fully into your face. No matter how cold or unpleasant the weather, have a window open, and open wide; and try to get a circulation of pure air through the room. Pile on the bedclothes, if necessary, to keep you warm; but have an unlimited supply of fresh air from out of doors. This is the first great requisite for healthy sleep.

The brain and nerve centers cannot be thoroughly vitalized if you sleep in "dead" or stagnant air; you must have the living atmosphere, vital with nature's Principle of Life. I repeat, do not make any compromise in this matter; ventilate your sleeping room completely, and see that there is a circulation of outdoor air through it while you sleep. You are not sleeping in a perfectly healthy way if you shut the doors and windows of your sleeping room, whether in winter or summer. Have fresh air. If you are where there is no fresh air, move. If your bedroom cannot be ventilated, get into another house.

Next in importance is the mental attitude in which you go to sleep. It is well to sleep intelligently, purposefully, knowing what you do it for. Lie down thinking that sleep is an infallible vitalizer, and go to sleep with a confident faith that your strength is to be renewed; that you will awake full of vitality and health. Put purpose into your sleep as you do into your eating; give the matter your attention for a few minutes, as you go to rest. Do not seek your couch with a discouraged or depressed feeling; go there joyously, to be made whole. Do not forget the exercise of gratitude in going to sleep; before you close your eyes, give thanks to God for having shown you the way to perfect health, and go to sleep with this grateful thought uppermost in your mind. A bedtime prayer of thanksgiving is a mighty good thing; it puts the Principle of Health within you into communication with its source, from which it is to receive new power while you are in the silence of unconsciousness.

You may see that the requirements for perfectly healthy sleep are not difficult. First, to see that you breathe pure air from out of doors while you sleep; and, second, to put the Within into touch with the Living Substance by a few minutes of grateful meditation as you go to bed. Observe these requirements, go to sleep in a thankful and confident frame of mind, and all will be well. If you have insomnia, do not let it worry you. While you lie awake, form your conception of health; meditate with thankfulness on the abundant life which is yours, breathe, and feel perfectly confident that you will sleep in due time; and you will. Insomnia, like every other ailment, must give way before the Principle of Health aroused to full constructive activity by the course of thought and action herein described.

The reader will now comprehend that it is not at all burdensome or disagreeable to perform the voluntary functions of life in a perfectly healthy way. The perfectly healthy way is the easiest, simplest, most natural, and most pleasant way. The cultivation of health is not a work of art, difficulty, or strenuous labor. You have only to lay aside artificial observances of every kind, and eat, drink, breathe, and sleep in the most natural and delightful way; and if you do this, thinking health and only health, you will certainly be well.