Persons in the enjoyment of complete health and vigor are frequently very sensitive to recognize the different agencies deleterious to their health. In the same way as animals they possess a certain instinct in this respect. In fact it is by this faculty alone that they can enjoy a normal and robust health, as they are thus enabled to avoid all kinds of dangers to their health, the integrity of their healthy mind also giving them the necessary will-power for this purpose.
Against all sorts of dangers to their health such persons, as a rule, are prompt to act; thus, when they come into a close room the air will soon become offensive to them, and they will either leave or ask for the opening of a window or of a ventilator, closed through folly. On the other hand sickly persons, or people who do not otherwise enjoy perfect health or well-balanced minds, will remain in such a vicious air and contract all the dangers consequent to it, shortening their prospects for a healthy youth and long life.
That living in the vitiated air of a close room is deleterious to health is proved by a simple observation of the faces of those stopping for a long time, or habitually doing so by reason of their professions, in close localities. They will present a pale, gray sickly appearance, and it is a fact that they very rapidly acquire all sorts of infections; especially is tuberculosis very prevalent in such cases. We observe precisely the same thing in the case of plants which, if kept in a close room, especially where little light reaches them, soon lose their color and are destroyed by parasites; and exactly the same happens in the case of man. Prisoners, unfortunate work-people, living and laboring in large numbers in small and close quarters, waiters and similar employees, are those in whom tuberculosis is most frequently found. In respect to workmen, this may be more truly the case in Europe, where they live under more miserable conditions, than in America, where their position is possibly the most enviable of all wage earners.
Close air, just as much as stagnant water, promotes the growth of dangerous microbes, and the chances of infection are greatly enhanced where a number of people are gathered together in such places. Many of them may be suffering from infectious diseases of the respiratory organs; they exhale, and also eject by coughing or sneezing, an enormous number of microbes, which mingle with the air and multiply at their leisure in such close atmospheres; and this is especially so when they are assisted in their growth by the great heat prevalent in such places, particularly in winter time. Bacteriological examinations made of the air of such localities have shown an enormous number of dangerous microbes. We need, therefore, not be surprised when persons, and especially children whose resistance is diminished, often contract tonsillitis, diphtheria, bronchitis, or pneumonia, etc., after having passed an evening in such a place, the air being hot, and particularly if, at the same time, the temperature outside was very low.
Living in a close room will soon tell on the general health, and this is easily visible in the appearance of such persons. Their pale faces form a striking contrast to the fresh rosy cheeks of those who habitually live in the fresh air. Those who have to pass their lives in offices are to be pitied, although, to a large extent, it is their own fault; they deprive themselves of the benefit of fresh air, which, after office hours, they would have ample opportunity to obtain if they would not persist in spending their leisure time in a club or other close place, instead of taking a brisk walk and exercise in the fresh air. No wonder that such people easily acquire dyspepsia and stomach troubles! Exercise in the open air is most valuable for promoting an appetite, and persons sitting constantly in close places often lack this; thus their gastric juice, which is indispensable to a thorough digestion (see chapter on hygiene of eating—how to obtain an appetite) fails, and eating without this juice their food will not be well digested and will create stomach troubles, which are extremely frequent in such office workers, but rarer in the case of peasants, coachmen, and other fortunate individuals whose occupation keeps them in the fresh open air. There is an increased amount of carbonic acid in the air of all localities where many persons are present. According to Pettenkofer, even in our living-rooms the carbonic acid content of the air is increased above the normal; and still more is this so in lecture-halls (3.2 per cent., against a normal content of 0.5 per cent.), in public houses (4.9 per cent.), and most of all in school rooms (7.2 per cent.).
We should, therefore, always keep a window open and never close the ventilator. Fresh air is the thing we are most in need of to carry on the oxidizing processes in our body. Exclude this and you exclude health. We must also remove from the rooms all those things which can absorb the air or hinder its entrance. There should never be flowers, and particularly no potted plants, in a living room, as they require air like ourselves; while to sleep in a room with plants is very deleterious (see chapter on sleep).
Curtains should all be removed, especially those of a heavy nature and dark color, which would prevent the entrance of the beneficial sunshine. Every room should be provided with openings for ventilation, and the transoms used in America are especially useful when they are open, and not used only to let the electric light into the sleeping room during the night, thus disturbing sleep. As a close room tends to shorten life it should be the policy of the government authorities never to allow the use of any newly built house, especially of public buildings, unless it contains openings for ventilation, the closing of which should be very severely punished by law.
If, during the day, it is necessary to have fresh air in every room, there is still greater necessity for this during the night, as we require more air during sleep than while awake; and, therefore, we should never sleep in a room that is entirely closed, but always leave the window (the upper part by preference) or the ventilator open.
We can easily convince ourselves how injurious it is to sleep in a close room by leaving our room in the morning, taking a walk in the fresh air, and then re-entering our sleeping chambers that have remained closed as we left them, and we shall at once realize the unhealthy condition of the air in such a room, filled as it is with carbonic acid that has been exhaled during the night, and also loaded with the other deleterious toxic substances cast off by our lungs and skin. We shall then certainly make up our minds not to inhale during the next night the same air again, but to allow it to escape by the open window and thus permit the entrance of fresh air into our lungs, whose need for air is much increased during sleep in order to replace the large volume of carbonic acid exhaled.
As a consequence of passing the night in such a close room, we feel, on the following morning, very heavy, and often have a headache; we also often have no appetite for breakfast after such a night, unless we first take a walk in the fresh morning air.
The danger of the close room should be brought home to all, even children, through instruction in hygiene in the public schools; and even from their very youngest days this should be instilled into the minds of youth, together with the contra-advantages of fresh air. By these means they will be accustomed to the fresh air and its beneficial effects, as much as they will learn to detest the horrors of the air exhaled by other people, which is the source of so many infections. Every one who wishes to enjoy life during youth, and live to a good old age, should abominate a close room and never, if he can possibly help it, pass an hour in such an atmosphere.