The average individual uses up in a minute’s time the oxygen contained in four bushels of air, and since the pregnant woman takes in through her lungs the oxygen for both herself and her baby, she must have a sufficient quantity of air to supply at least this amount. Accordingly, you should make a point of spending at least two hours of each day in the open air. If the weather is so stormy or severe as to make it undesirable for you to go out from under cover, because of the danger of getting wet or chilled, you can wrap up well and take your airing on a protected porch or in a room with all the windows wide open. But this is only a part of it, for the air in your house or rooms must be kept fresh all day by being constantly changed; this requires a steady inpouring of fresh air and outpouring of stale air. A very good way to accomplish this is to have one or more windows open slightly, top and bottom, all the time. But there must be no sudden changes of temperature, nor drafts, for fear of chilling your skin. At night you should sleep in a room with the windows open, taking care to be well protected by light, warm coverings. =Exercise.= Each detail of the expectant mother’s daily routine seems to be more important than the last. And so when we come to the question of regular out-of-door exercise we are almost persuaded to believe that whatever else may be neglected, this is indispensable, since it promotes digestion, stimulates the activity of the skin and lungs, steadies the nerves, quiets the mind and promotes sleep. And more than that, walking, which is probably the most satisfactory form of exercise for her to take, also strengthens some of the muscles that are used during labor. But exercise is downright injurious if continued to the point of fatigue, no matter how little has been taken. Each woman must be a law unto herself in this matter, therefore, and must be impressed with the importance of stopping before she is tired. It may be a good plan for you to start by walking only a short distance at a time, increasing this gradually until you are able to walk possibly as much as an hour in the morning and an hour in the afternoon without fatigue. All violent exercise and sports are of course to be avoided, particularly swimming, horseback riding and tennis. While motoring and carriage driving are pleasant diversions, they cannot be classed as exercise. They should be taken only in comfortable vehicles and over smooth roads, so that there will be no jarring nor jolting, and the expectant mother should not do the driving herself.