[Illustration: FIG. 74. A window tent. (Invented by Dr. W. E. Walsh.)] [Sidenote: How to have fresh air at home:] If you have only a single window in your room, try to sleep with your head in the fresh air. It is not always easy to arrange a room in such a way that you can have fresh air without placing your bed in a draft, but even this difficulty can be overcome. [Sidenote: (_1_) By window tents] There are several devices, called window tents, which you can buy. By the use of such a tent, your head will be out-of-doors all the time; yet the draft cannot strike your body, because a part of the tent fits around your neck and cuts off the air from the rest of your body. One of these tents is shown in Figure 74. You do not put your head out of the window; your head is on your pillow just as if the tent were not there. Your bed is placed directly in front of the window and the tent comes down over your pillow, allowing your head practically to be out-of-doors, but keeping the cold air out of the room. Sleeping under a window tent is the next best thing to sleeping out-of-doors. [Illustration: FIG. 75. A sleeping porch built in a house.] [Sidenote: (_2_) By sleeping porches] Many of our modern houses are built with sleeping porches on which one can sleep outdoors summer and winter. Where there is not a special sleeping porch on the house, an ordinary porch may often be made to serve the purpose, or a very inexpensive sleeping porch can be added to the house. [Sidenote: (_3_) By tent cots] Sometimes people cannot get the use of a porch of any kind. In such cases it may be possible to put up a tent in the yard. If the yard is very small, a tent cot may be used. This is simply a cot with a tent on it, which can be closed up and put away in the daytime and set up again at night. In a large city where the houses have no yards at all, this arrangement can be used by setting it up on the roof of the house. There is almost always some way of securing fresh air at night if we will only give a little thought to the matter. [Sidenote: Fresh air in schoolrooms] Unfortunately, many of our school buildings are not provided with good ventilating plants. A proper system of ventilation furnishes at least 1200 cubic feet of fresh air per hour for each child in each room. [Illustration: FIG. 76. An open-air schoolroom for consumptive children.] [Sidenote: The necessity for playgrounds] In large cities it is often impossible to find outdoor space in which boys and girls may play during recess. Even this difficulty can be overcome by turning the roof of the school building into a playground, with a high wire netting around it.