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How And Why We Breathe
Category: HOW TO KEEP THE LUNG-BELLOWS IN GOOD CONDITION
Source: A Handbook Of Health
Life is Shown by Breathing. If you wanted to find out whether a little
black bunch up in the branches of a tree were a bird or a cluster of
leaves, or a brown blur in the stubble were a rabbit or a clod, the
first thing you would probably look for would be to see whether it
moved, and secondly, if you could get close enough without its moving
away, whether it were breathing. You would know perfectly well if you
saw it breathing that it was alive, and that, if it were not breathing
at all, it would probably be dead, or very nearly so.
Why is breathing so necessary to life that it lasts practically as long
as life does, and when it stops, life stops too? Animals can stop eating
for days, or even weeks, and yet live, especially if they were fairly
fat when they began to fast. Indeed, some animals, like woodchucks,
bears, and marmots, will go to sleep in the fall, and sleep right on
through to spring without eating a mouthful. But if any animal or bird
is prevented from breathing for three minutes, it will die.
Short Storage Supply of Air. There is a difference between the kind of
things that you take in when you breathe and the kind of things you take
in when you eat or drink. Food and drink are solids and liquids; and the
body is a great sponge of one soaked full of the other, so that large
amounts of food and water can be stored up in the body. But what you
take in when you breathe is, of course, air--which is neither a solid
nor a liquid, but a gas, very light and bulky. Of gases the body can
soak up and hold only a very small amount; so its storage supply of
them will be used up completely in about three minutes, and then it dies
if it cannot get more air.
Why our Bodies Need Air-Oxidation. The body is made up of millions of
tiny living animals called cells, which eat the food that is brought to
them from the blood and pour their waste and dirt back again into the
same current. Now, what would happen if we were to throw all the garbage
from the kitchen, and the wash water from the kitchen sink, and the
dirty water from the bathroom right into the well out of which we pumped
our drinking water? We should simply be poisoned within two or three
days, if indeed we could manage to drink the disgusting mixture at all.
That is exactly what would happen to our body cells if they were not
provided with some way of getting rid of their waste and dirt.
Part of the waste that comes from our body cells is either watery, or
easily dissolved in water; and this is carried in the blood to a
special set of filter organs--the liver and the kidneys--and poured out
of the body as the urine. Another part of it, when circulating through
the skin, is passed off in the form of that watery vapor which we call
perspiration, or sweat. But part of the waste can be got rid of only by
burning, and what we call burning is another name for combining with
oxygen, or to use one word--oxidation; and this is precisely the
purpose of the carrying of oxygen by the little red blood cells from the
lungs to the deeper parts of the body--to burn up, or oxidize, these
waste materials which would otherwise poison our cells. When they are
burnt, or oxidized, they become almost harmless.
Why the Red Cells Carry only Oxygen to the Body. But why do not the
red cells carry air instead of just oxygen? This is simply a clever
little economy of space on nature's part. As a chemist will tell you the
air which we breathe is a mixture of two gases--one called nitrogen and
the other oxygen; just as syrup, for instance, is a mixture of sugar and
water. Then too, as in syrup, there are different amounts of the two
substances in the mixture: as syrup is made up of about one-quarter
sugar and three-quarters water, so air is made up of one-fifth oxygen
and four-fifths nitrogen. Now the interesting thing about this mixture,
which we call air, is that the only really live and vital part of it
for breathing purposes is the one-fifth of oxygen, the four-fifths of
nitrogen being of no use to our lungs. In fact, if you split up the air
with an electric current, or by some other means, and thus divide it
into a small portion of pure oxygen (one-fifth), and a very much larger
portion (four-fifths) of nitrogen, the latter would as promptly
suffocate the animal that tried to breathe it as if he were plunged
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
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 passage. 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
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
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
passes in and out again.
When you stand at the window on a cold day, the glass 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 principal 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 glass or a bottle two-thirds full of
lime water, and breathe into it through a glass 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
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.
Next: The Need Of Pure Air
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