A Handbook of Health Part 11

It may perhaps be difficult to think of anything burning inside of your bodies where everything is moist, especially as you do not see any flame; but you do find there one thing which always goes with burning, and that is warmth, or heat. This slow but steady and never-ceasing burning, or oxidation, of the waste and dirt inside your bodies is what keeps them warm. When you run fast, or wrestle, or work hard, your muscle-cells work faster, and make more waste, and you breathe faster to get in the oxygen to burn this up--in other words, you fan the body fires, and in consequence you get a great deal hotter, and perhaps perspire in order to get rid of your surplus heat.

The Ocean of Air. Where does the blood in the body go in order to get this oxygen, which is so vital to it? Naturally, somewhere upon the surface of the body, because we are surrounded by air wherever we sit, or stand, or move, just as fishes are by water. All outdoors, as we say, is full of air. We are walking, just as fishes swim, at the bottom of an ocean of air some thirty miles deep; and the nearer we get up toward the surface of that ocean, as, for instance, when we climb a high mountain, the lighter and thinner the air becomes. Above ten thousand feet we often have great difficulty in breathing properly, because the air is so thin and weak in oxygen.

How the Lungs Grew Up. In the simplest forms of life, any part of the soft and delicate surface will do for the blood to reach, in order to throw off its load of carbon "smoke" and take on its supply of oxygen.

In fact, animals like jellyfish and worms are lungs all over. But as bodies begin to get bigger, and the skin begins to toughen and harden, this becomes more and more difficult, although even the highest and biggest animals like ourselves still throw off a certain amount of this carbon dioxid and other gases through the skin. Accordingly, certain parts of the surface of the body are set apart specially for this business of breathing; and as we already have an opening into the body provided by the mouth and food tube, the simplest thing to do is to use the mouth for taking in air, when it is not being used for taking in food, and to set aside some part of the food tube for breathing purposes.

[Ill.u.s.tration: DIAGRAM OF THE AIR TUBES AND LUNGS

The arrows show the direction of the incoming air.]

The lungs sprout out from the front of the gullet, just below the root of the tongue, in the days when we are getting ready to be born. The sprout divides into two, forming the beginning of the pair of lungs.

Each lung sprout again divides into two, and each of the two smaller buds again into two, until finally we have the whole chest filled up with a "lung-tree" whose trunk stems and leaves are hollow. The stem of the tree or bush becomes the windpipe (_trachea_). The first two branches into which it divides form the right and left lung tubes, known as _bronchi_. The third, fourth, fifth, sixth, etc., divisions, and so on, form what are known as the _bronchial tubes_. These keep on splitting into tinier and tinier twigs, until they end, like the bush, in little leaves, which in the lung, of course, are hollow and are called the air cells (_alveoli_). This budding off of the lungs from the gullet is the reason why the air we breathe and the food we swallow go down the same pa.s.sage. Every mouthful of our food slides right across the opening of the windpipe, which has to be protected by a special flap, or trap-door of gristle, called the _epiglottis_. If you try to eat and talk at the same time, the epiglottis doesn't get warning of the coming of a swallow of food in time to cover the opening of the windpipe, and the food goes down the wrong way and you cough and choke.

Now, if you will just place your fingers upon the front of your neck and slide them up and down, you will, at once, feel your windpipe--a hard, rounded tube with ridges running across it,--while, no matter how carefully you feel, or how deeply you press, you cannot feel your gullet or esophagus at all. Just take a mouthful of water, however, put your fingers deeply on each side of the windpipe, and swallow, and you will feel something shoot down the esophagus, between your fingers, toward the stomach.

Both of these tubes were made of exactly the same materials to begin with. Why have they become so different? A moment's thought will tell you. One, the gullet, has only to swallow solid food or drink, so that its walls can remain soft, and indeed fall together, except when it is actually swallowing. The other tube, the air-pipe or windpipe, has to carry air, which neither will fall of its own weight, nor can readily be gulped down or belched up. It is absolutely necessary that its walls should become stiff enough to keep it open constantly and let the air flow backward and forward. So we find growing up in the walls of this air pipe, cells which turn themselves into rings of gristle, or cartilage.

What the Breath Is. As you know, your "breath," as you call it,--that is to say, the used-up air which you blow out of your lungs,--is different in several ways from pure, or unused air. In the first place, it is likely to have a slight musky or mousy odor about it. You never like to breathe any one else's breath, or have any one breathe in your face. This dislike is due to certain gases, consisting of impurities from the blood, the cells of the lungs, the throat, the nose, and, if the mouth is open, the teeth. These are not only offensive and disagreeable to smell, but poisonous to breathe.

Then your breath is much warmer than the rest of the air. In fact, on a very cold morning you may have tried to warm up your fingers by breathing on them; and you have also noticed that if a number of people are shut up in a room with doors and windows closed, it soon begins to feel hot as well as stuffy. This heat, of course, is given off from the blood in the lungs and in the walls of the throat and nose, as the air pa.s.ses in and out again.

When you stand at the window on a cold day, the gla.s.s just in front of your mouth clouds over, so that you can no longer see through it; and if you rub your finger across this cloud, it comes away wet. Evidently, the air is moister than it was when you breathed it in; this moisture also has been given off from the blood in the lungs.

But what of the princ.i.p.al waste gas that the blood gives off in the lungs--the carbon "smoke," or carbon dioxid? Can you see any trace of this in the breath? No, you cannot, for the reason that this gas is like air, perfectly clear and transparent, and never turns to moisture at any ordinary temperature. But it has a power of combining with certain other things and forming substances which, because they are combinations of carbon, are called _carbonates_. The commonest substance with which it will do this is lime. If you take a gla.s.s or a bottle two-thirds full of lime water, and breathe into it through a gla.s.s tube or straw, you will see in a very few minutes that it is becoming milky or cloudy from the formation of visible carbonate of lime, which, when you get enough of it, makes ordinary limestone. So, although you cannot see, or smell, this carbon "smoke" in your breath, you can readily prove that it is present.

[Ill.u.s.tration: "IMPROVING THEIR WIND"]

How and Why our Breathing Varies. When you run or wrestle, you breathe faster in order to draw more air into the lungs. At the same time, your heart beats faster in order to drive a larger amount of blood through the lungs. If you run too far, or wrestle too hard, your heart and your lungs both go faster and faster, until finally they reach a point when they cannot go any quicker, and the poisonous waste substances are formed in your muscles faster than they can possibly be burned up, even by the quickest breathing and the hardest pumping of your heart. Then you begin to get "out of breath"; and if you were compelled--in order to save your life, for instance--to keep on running, or fighting, you would at last be suffocated by your own waste and dirt, and fall exhausted, or unconscious.

On the other hand, by carefully training your muscles and your heart and your lungs by exercises of various sorts in the open air, beginning with easy ones and going on to harder and longer ones, you can "improve your wind," so that your heart will be able to pump more blood through the lungs per minute, and your lungs will be able to expand themselves more fully and more rapidly without fatigue.

If you can recall having had a fever of any sort, even a slight one, such as comes with a sore throat or a bad cold, you may remember that you breathed faster and that your heart beat faster, and yet you were not doing any work with your muscles. The cause, however, is the same; namely, the amount of waste that is being produced in the body--in this case, by the poisons (toxins) of the germs that cause the fever. The more waste that is formed in the body, the more effort the heart and lungs will make to try to get rid of it.

The Ribs. How does the air get in and out of the lung tubes? Evidently you do not and cannot swallow it as you would food or drink; and as it will not run down of its own accord when you simply open your mouth, nature has had to devise a special bit of machinery for the purpose of sucking it in and pressing it out again. This she has done in a rather ingenious manner by causing certain of the muscle-rings in the wall of the chest to turn first into gristle, or cartilage, and then later into bone, making what are known as the _ribs_; these run round the chest much as hoops do round a barrel, or as the whalebone rings did in the old-fashioned hoop skirt. When the muscles of the chest pull these ribs up, the chest is made larger,--like a bellows when you lift the handle,--air is sucked in, and we "breathe in" as we say; when the muscles let go, the ribs sink, the chest flattens and becomes smaller, the air is driven out, and we "breathe out."

FOOTNOTES:

[18] This nitrogen, though of no value for breathing, is of great value as a food, forming, as we have seen, an important part of all meats, or proteins, which build the tissues of our bodies. It can, however, be taken from the air only with great difficulty, by a very roundabout route; the bacteria of the soil eat it first, then they pa.s.s it on as food to the roots of plants; animals eat plants, and we eat the animals, and thus get most of our nitrogen.

CHAPTER XIV

HOW TO KEEP THE LUNG-BELLOWS IN GOOD CONDITION

THE NEED OF PURE AIR

Free Air is Pure. As air, in the form of wind, actually sweeps all outdoors, day and night, it clearly is likely to pick up a good many different kinds of dust and dirt, which may not be wholesome when breathed into our lungs. Fortunately, nature's great outdoor system of purifying the air is almost perfect, so that it is only when we build houses and shut in air from the great outdoor circulation, that "dirt"

that is really dangerous begins to get into it. Caged air is the only air that is dangerous. Free-moving air is always perfectly safe to breathe any hour of the day or night, or any season of the year.

Shut-in and Stagnant Air is Foul. This restless air-gas cannot be stored outside of the body, any better than it can be inside. For one thing, it is too bulky; and for another, it begins to become impure in various ways, as soon as it is shut up. It is the most unmanageable food that we "eat," for we can neither cook it nor wash it like solid food, nor filter it nor boil it like water, except on a very limited scale. We can do nothing to it except to foul it, which we do with every breath that we breathe, every fire that we make, every factory that we build.

Our only chance of safety, our only hope of life, is to connect every room and every corner of those little brick and mortar boxes, those caged sections of out-of-doors, that we call houses, with nature's great system of air supply, "All Outdoors." Fortunately, the only thing needed to make the connection is to open a window--no need to send for a plumber or put in a meter, and there is no charge for the supply after connections have been made.

The Enormous Amount of Air. Air outdoors is everywhere, for practical purposes, absolutely pure, just as water is when it comes down from the clouds. And like water, its only dangerous impurities are what we put there ourselves. The purity of outdoor air is due mainly to the fact that there is such an enormous amount of it, not only the miles and miles of it that stretch away on every side of us, but nearly thirty miles of it straight up above our heads; its purity is also due to the fact that, like water, it is always in motion. When heated by the sun, it expands; and, in doing so, it rises because it is less dense and therefore lighter. As soon as the pressure of the air above is lessened, air rushes in below from all the cooler regions around. This rushing of air we call a _wind_. If the low pressure lies to the north of us, the air rushes northward over us to fill it, and we say the wind is from the south; if the air is flowing to the south of us, we say the wind is from the north.

How Air is Purified. In these winds certain small amounts of dust, or dirt, or leaf mould are whirled up into the air, but these are promptly washed down again whenever it rains; and the same is true of the smoke impurities in the air of our great cities. Air is also constantly being purified by the heat and light of the sunbeams, burned clean in streaks by the jagged bolt of the lightning in summer, and frozen sweet and pure by the frosts every winter. So that air in the open, or connected with the open, and free to move as it will, is always pure and wholesome. But to be sure of this, it must be "eaten alive"--that is, in motion.

Stagnant air is always dead and, like all dead things, has begun to decay.

The Carbon Dioxid in the Air. Air, as you will remember (p. 132), is a mixture of oxygen and nitrogen, and its value in the body is that it gives off part of its oxygen to combine with the body wastes and burn them to carbon dioxid. Oddly enough, even pure outdoor air contains tiny traces of carbon dioxid; but the amount is so very small as to be of no practical importance, in spite of the fact that every kind of animal that lives and moves upon the earth is pouring it out from his lungs every second. The rapidity with which it disappears is due in part to the rapidity with which it rises and spreads, or is blown, in every direction; and in part to the wonderful arrangement by which, while animals throw off this poisonous gas as waste, plants eagerly suck it in through the pores in their leaves and eat it, turning it into the carbohydrates, starch and sugar, which, in turn, become valuable foods for the animals. So perfect is this system of escape, or blowing away, of carbon dioxid, combined with its being eaten up by plants, that even the air over our great cities and manufacturing towns contains only the merest trifle more of carbon dioxid than that over the open country. Its other smoke-impurities, dirts and dusts, escape, or are blown away so rapidly that they are seldom thick enough to be injurious to health, except in the narrowest and darkest streets; so that it is always safe to open your windows wide for air, wherever you may live. The princ.i.p.al danger from smoke is that it cuts off the sunlight.

The Necessity for Ventilation--Impurities of Indoor Air. The worst impurities in air are those that come from our own breaths and our own bodies; and, unexpectedly enough, carbon dioxid is not one of them. In spite of hundreds of experiments, we do not yet know exactly what these impurities are, though they are doubtless given off from our lungs, our skins, our mouths, and teeth, especially if the latter are not kept clean and sweet, but left dirty and decaying.

We do know, however, to a certainty that air shut up in a room, or house, with people, rapidly becomes poisonous and unwholesome. As we breathe on an average about eighteen or twenty times to the minute when we are grown up, and twenty-five to thirty times a minute when we are children, you can readily see how quickly the air in an ordinary-sized room will be used up, and how foul and unfit for further breathing it will become from being loaded with these bad-smelling lighter gases, with the carbon "smoke," with heat, and with moisture. The only way in which a room can be kept fit for human beings to breathe in is to have a draught, or current of air, pouring into it through open windows, or open doors, or ventilating shafts, at least as rapidly as it is being breathed by the persons who occupy that room. By hundreds of tests this has now been found to be on an average about four bushels a minute for each person, and any system of proper ventilation must supply this amount of air in order to make a room fit to sit in.

If a man, for instance, accidentally gets shut into a bank-vault, or other air-tight box or chamber, it will be only a few minutes before he begins to feel suffocated; and in a few hours he will be dead, unless some one opens the door. A century ago, when the voyage from Europe to America was made in sailing vessels, whenever a violent storm came up, in the smaller and poorer ships the hatches were closed and nailed down to keep the great waves which swept over the decks from pouring down the cabin-stairs and swamping the ship. If they were kept closed for more than two days, it was no uncommon thing to find two or three children or invalids among the unfortunate emigrants dead of slow suffocation; and many of those who were alive would later have pneumonia and other inflammations of the lungs. On one or two horrible occasions, when the crew had had a hard fight to save the ship and were afraid to open the hatches even for a moment, nearly one-third of the pa.s.sengers were found dead when the storm subsided. So it is well to remember that we are fearfully poisonous to ourselves, unless we give nature full chance to ventilate us.

There are also other ways in which the air in houses may be made impure besides by our own bodies, but none of them is half so serious or important. All the lights that we burn in a house, except electric ones, are eating up oxygen and giving off carbon dioxid. In fact, a burning gas jet will do almost as much toward fouling the air of a room as a grown man or woman, and should be counted as a person when arranging for ventilation.

If gas pipes should leak, so that the gas escapes into a room, it is very injurious and unwholesome--indeed, in sufficient amounts, it will suffocate. Or, if the sewer pipes in the walls of the house, or in the ground under the cellar, are not properly trapped and guarded, _sewer gas_ may escape into the house from them, and this also is most unwholesome, and even dangerous.

Cellar and Kitchen Air. Houses in which fruit and vegetables are stored in the cellar become filled with very unpleasant odors from the decay of these. Others again, where the kitchen is not properly ventilated, get the smoke of frying and the smell of cooking all through them. But such sources of impurity, while injurious and always to be strictly avoided, are neither half so dangerous when they occur, nor one-tenth so common as the great chief cause of impure air--our breaths and the other gases from our bodies, with the germs they contain.

Drafts not Dangerous. Now comes the practical question, How are we to get rid of these breath-poisons? From the carelessness of builders, and the porous materials of which buildings are made, most houses are very far from air-tight, and a considerable amount of pure air will leak in around window-casings, door-frames, knot-holes, and other cracks, and a corresponding amount of foul air leak out. But this is not more than one-fifth enough to keep the air fresh when the rooms are even partially occupied, still less when they are crowded full of people. As each individual, breathing quietly, requires about four bushels of air (one and a half cubic yards) a minute, it is easy to see that, when there are ten or more people in a room, there ought to be a steady current of air pouring into that room; and when there are twenty or even forty people, as in an average schoolroom, the current of air (provided there _is_ one) must move so fast to keep up the supply that the people in the room begin to notice it and call it "a draft." It would be difficult to ventilate a room for even four or five persons without producing, in parts of it, a noticeable draft of air. In fact, it is pretty safe to say that, if somebody doesn't feel a draft the room is not being properly ventilated. At one time this was considered a very serious drawback--drafts were supposed to be so dangerous. But now we know that a draft is only air in motion, and that air in motion is the _only air that is sure to be pure_. There is nothing to be afraid of in a draft which is not too strong, if you are clean outside and in, and reasonably vigorous. If the draft is too strong, move away from the window or the door. Colds are very seldom caught from the cold, pure air of a draft, but nearly always from the germs, or dirt, in the still, foul air of a tightly closed room. This fact has swept away the chief objection to the _direct_, or natural, method of ventilating through open windows.

Methods of Ventilation. Fortunately, as often happens, the simplest and most natural method of ventilation is the best one. Open the windows, and let the fresh air pour in. If there be any room which hasn't windows enough in it to ventilate it properly, it is unfit for human occupation, and is seldom properly lighted. Most elaborate and ingenious systems of ventilation have been devised and put into our larger houses, and public buildings like libraries, court-houses, capitols, and schools. Some of them drive the air into each room by means of a powerful steam, or electric, fan in the bas.e.m.e.nt; others suck the used-up air out of the upper part of each room, thus creating an area of low pressure, to fill which the fresh air rushes in through air-tubes or around doors and windows. They have elaborate methods of warming, filtering, and washing the air they distribute. Some work fairly well, some don't; but they all have one common defect--that what they pump into the rooms is not _fresh_ air, though it may conform to all the chemical tests for that article. "The proof of the pudding is in the eating," and fresh air is air that will make those who breathe it _feel_ fresh, which the cooked and strained product of these artificial ventilating systems seldom does.

[Ill.u.s.tration: THE "DARK ROOM" DANGER OF THE TENEMENTS

The rooms "ventilate" from one to another; bedroom, dining-room, and kitchen being practically one room, with only one window opening to the _outer air_. Most of the old small tenements were built on this plan and are accountable for much of the lung disease in cities to-day.]

If they could be combined with the natural, window system of ventilation, they would be less objectionable; but the first demand of nearly all of them is that the windows must be kept shut for fear of breaking the circuit of their circulation. Any system of ventilation, or anything else, that insists on all windows being kept shut is radically wrong. It is only fair to say, however, that most of these systems of ventilation attempt the impossible, as well as the undesirable thing of keeping people shut up too long. No room can be, or ought to be, ventilated so that its occupants can stay in it all day long without discomfort. In ventilating, we ought to _ventilate the people in the room_, as well as the room itself. This can only be done successfully by turning the people out of doors, at least every two or three hours if grown-ups, and every hour or so if children. That is what school recesses are for, and they might well be longer and more frequent.

[Ill.u.s.tration: VENTILATING THE PUPILS, AS WELL AS THE CLa.s.sROOM]

The first and chief thing necessary for the good ventilation of houses and schools is plenty of windows, which are also needed to give proper light for working purposes, and to let in the only ever-victorious enemy of germs and disease--sunlight.

Secondly, and not less important, the windows should fit properly, and be perfectly hung and balanced, so that the sash will come down at a finger's touch, stay exactly where it is put, and go up again like a feather, instead of having to be pried loose, wrested open, held in place with a stick, and shoved up, or down again, only with a struggle.

[Ill.u.s.tration: A WELL-AIRED CLa.s.sROOM

The windows to the left of the pupils cannot, of course, be shown in the picture, but it can be seen that the lighting of the room is chiefly from that side. Notice that the windows are both down from the top and up from the bottom.]

There should be, if possible, windows on two sides of every room, or, if not, a large transom opening into a hall which has plenty of windows in it. With this equipment and a good supply of heat, any room can be properly ventilated and kept so. But it _will not ventilate itself_.

Ventilation, like the colors of the great painter Turner, must be "mixed with brains"; and those brains must be in the room itself, not down in the bas.e.m.e.nt. In the schoolroom, each teacher and pupil should regard the ventilation of the room as the most important single factor in the success of their work. The teacher has a sensitive thermometer and guide in, first, her own feelings and, second, the looks and attention of her pupils. There should be vacant seats or chairs in every room so that those too near the window in winter can move out of the strong current of cold air.