The effects of insufficient ventilation are perhaps less during our waking hours than during sleep. Most per sons move about a good deal during the day and are in and out of doors. Moreover, the lungs are active, and if the air is impure, they may make up the deficiency by more frequent respi ration. When a person is conscious, the discomfort of close air, resulting in headaches and a sense of incipient suffocation, affords warning that it is time to change the air in the room or take a walk outside. But a sleeper is usually unconscious of any warning sensations. The respiration is slower, and there is nothing to check the evil effects of breathing again and again the air that has been robbed of its oxygen. The result is the impairment of all the vital processes that normally make up during sleep for the daily wastes of the body. Hence sleeping in poorly ventilated rooms leads im mediately to headaches, a sense of having rested badly, with exhaustion and fatigue, and eventually to such wasting diseases as consumption, ca tarrh, and other affections of the head, throat, and lungs.
The Fresh-air Cure.—It is now well known that consumption, the most wasting and fatal of all human dis eases, can be cured in many cases by simply breathing pure air out of doors, both day and night. Modern sani tariums have sleeping porches of can vas or tents in which patients sleep out of doors, even in cold climates in winter, the body being protected by suitable covering. The contrast be tween slow suffocation from lack of ventilation and the cure of consump tion by breathing pure air both day and night should impress upon every one the absolute necessity of thor ough ventilation, especially in sleeping apartments.
When to Ventilate.—It is es sure indication that, when the air in a room seems close and has a musty odor to a person coming in from outdoors, it is so impure as to be injurious to health. If, after stepping into the open air in the morning and taking a few deep breaths, one returns to a sleeping room and finds the air insuf ferably close, the room has not been sufficiently ventilated during the night, and evil consequences are sure to follow.
Or place a shallow glass dish con taining lime water in a room to de termine the presence of carbonic-acid gas. If there is much of this sub stance present the water will quickly become cloudy.
Or, to test for marsh gas, sewer gas, and the like containing sulphureted hydrogen, expose to the air moist car bonate of lead, which will turn black if this substance is present.
Night Air.—There is a superstition prevalent in many parts of the country that night air is injurious. There may be some ground for this belief where the Anopheles mosquito its abroad in malarial districts, or the vicinity of swamps wherever a mist may arise at night and spread contamination. But
in most localities this notion is en tirely groundless and misleading. If we do not breathe night air at night, pray what shall we breathe? Either it is necessary to breathe over and over the air that has been in the sleeping room all day, or else to admit fresh air from outdoors, and whatever the dan ger in breathing night air, it is certain ly less immediate than quick or slow suffocation from lack of ventilation.
To Ventilate Bedrooms.—The prob lem of ventilation is twofold: first, to let in the pure air; second, to let out that which is impure. There should be windows on two sides of the bed room, and also, if possible, a fireplace for ventilation. The bed should be located so that the air will circulate freely around and beneath it without a draught. If possible, the door when open should screen the bed, or a screen should be interposed when necessary between the bed and the open door or window.
The simplest means of ventilation is to lower the upper sash of a window for several inches and raise the lower sash either of the same window or of one on the opposite side of the room. If there is an open fireplace in the room, it will remove the impure air by creating a draught and causing suction.
Or lower the upper sashes of two windows opposite one another.
Or open the bedroom door and ad mit the fresh air to an adjacent room or hall by means of two or more win dows in such a way that a draught passing near the bedroom door will create suction and draw the impure air out of it. The direction of these air currents may be determined by holding a lighted match or candle in them.
Just before retiring open all the windows and change the air in the room.
To Prevent Dranghts.—To prevent a direct current of air crossing the bed on raising a window sash, take a piece of any firm, tightly woven cloth, as duck or light canvas or strong flan nel goods, the width of the window and about eighteen inches deep. Make a heading at top and bottom to admit sash-curtain rods. Adjust one rod at the bottom of the window frame and the other about twelve or fourteen inches higher up. Thus when the sash is lifted as high as the upper rod the entering current of air will cause the cloth to belly out into the room, and the current will be turned on both sides and driven along the wall. A current of air, like a current of water, has a tendency to stick to any surface over which it flows; hence the air will follow along the wall, and even to some extent around the corners of the room, as can be seen by testing with the flame of a candle.