MOTHER: If I use any words that you do not understand you must ask what
they mean. The pulse is the beating or throbbing of the arteries caused
by the blood flowing through them from the heart. Have you noticed how
the water sometimes goes in jerks as it is pumped through the hose pipe
in the garden? It is that way with the heart. Each beat sends the blood
through the arteries in jerks, and when we place our fingers on them,
we can tell how fast the heart is beating. That is called the pulse.
AMY: Sometimes I think that I can hear my heart beating.
MOTHER: Each time it beats it makes two sounds, and they can be heard
if the ear is placed over the heart. The doctor can tell by these
sounds whether the heart is working all right.
PERCY: But I should think it would get tired out if it keeps at work
all the time.
MOTHER: So it would if it had no rest. Every part of the body must
rest. Between the heart-beats there is just a little rest, and, though
the time is very short, yet if it were all put together it would amount
to six or eight hours a day.
HELEN: If the heart beats sixty or seventy times a minute, I wonder how
many times it beats in a day.
MOTHER: You may do a little figuring to find out. Seventy beats a
minute, sixty minutes an hour, and twenty-four hours a day.
ELMER: I have it. It would be more than one hundred thousand.
┌─────────┐
│ 70 │
│ 60 │
│ ———- │
│ 4,200 │
│ 24 │
│ ———- │
│ 16800 │
│ 8400 │
│ ———- │
│ 100,800 │
└─────────┘
MOTHER: And this means hard work, too; for if all it does in
twenty-four hours were done at once, it would be equal to lifting one
hundred and twenty tons of stone one foot from the ground.
PERCY: Whew! I should think this was a powerful little force-pump, sure.
MOTHER: But what would you think of a man who made his heart beat six
thousand times more in twenty-four hours, which means that it must lift
seven tons more than it should?
Amy: But I thought the heart kept working of itself. Then how _could_
any one make it do more?
MOTHER: By taking only two ounces of alcohol in a day the heart would
be overworked as I have said. It would not only have its regular work
to do, but it would do that amount extra to throw out the poison it
finds in the blood; for it knows it is an enemy. See, I have taken the
pendulum off the clock for a minute. Now what has happened?
ELMER: It ticks much faster, and will soon run down.
MOTHER: It is much the same way with the heart of a person who takes
drink with alcohol in it. His heart beats faster; his face gets red,
and he can think and talk fast. It is like an engineer putting on steam
and sending his train at lightning speed down a steep grade. If nothing
worse happens, he will find when he comes where the track is up-grade
that his power is gone and he has wasted his steam. The clock runs fast
with the pendulum off, but it soon “runs down,” we say, and it is the
same with the boy or the man who drinks. There are nerves which act on
the heart as brakes do on the train. They keep it steadily at work and
do not let it beat too fast. There is another way that alcohol hurts
the heart.
HELEN: Please tell us how.
MOTHER: It changes the strong muscle walls into fat. The heart grows
larger than it should be, and becomes so weak that it can not send the
blood over the body as it should. The man has hard work to breathe. He
gets the dropsy and other ailments, and perhaps dies of “heart failure.”
PERCY: Does tobacco affect the heart, mother?
MOTHER: Yes; it makes its beat unsteady, and sometimes causes an
illness which doctors call “tobacco heart.” It also makes it work
harder than it ought.
AMY: What can we do to keep the heart well and strong?
[Illustration: _YOU “CAN RUN, JUMP, AND SWING.”_]
MOTHER: Be sure to give it good blood to send over the body. You need
not keep still for fear that you will break this curious little pump;
for, like the engines in ships, it is made to be tumbled about. Boys
and girls can run, jump, and swing, yet the little engine keeps on with
its steady hub tub against the walls of the house, and we would hardly
know it was there. Good, honest labor makes the heart work better,
and sends the blood running swiftly to every part of the body. We say
when we are cold that a brisk walk will “start the blood;” that is,
the heart beats more quickly, and soon the whole body becomes warm. We
might say that the heart is like a clock, as well as an engine. If I do
not wind the clock, what happens?
PERCY: It runs down.
MOTHER: Does some one need to wind up your heart each day to keep it
beating?
HELEN: Oh, no; it just keeps going itself!
MOTHER: God keeps it beating, sometimes for a hundred years, without
our help. I read a little poem not long ago about the heart, which I
will repeat for you:—
THE CLOCK OF LIFE.
“Oh, did you ever think, my child,
That in your body dwells
A tiny clock, that verily
All other clocks excels?
“It needs no key to wind it up,
No oiling of the wheels,
No jeweler to make repairs;
With such it never deals.
“Near seventy ticks a minute is
Its normal race to go;
Just place your thumb against your wrist,
And you will find it so.
“This little clock was made to be
A faithful sentinel,
To give alarm of any change
Within its prison cell.
“If you are healthy, then its ticks
Are even, full, and strong;
By this you know that, in its cell,
Nothing is going wrong.
“When sickness comes, it works so hard,
And is so feeble, too,
It can not keep the perfect time
Its Maker meant it to.
“Now, would you help this little clock
The best of time to keep?
Then always mind the rules of health,
And thus their blessings reap.”
—_Mrs. Julia Loomis._
[Illustration: A clock]
THE CARETAKER
AMY: Just see, mother! I have cut my finger. See how fast the blood
runs out! Oh-h!
MOTHER: Suppose we let a drop fall on this glass and then try to
find out what it is made of, what it does in the body, and about the
different rooms it visits. You may ask questions and I will try to
answer them; but first we will bind up the cut finger in this bit of
soft cloth. We have already learned how blood is made, but we want to
learn what it does for us.
Blood is made from the food you eat and the water you drink. If you eat
good food it makes good blood. Bad food and drink make bad blood. It
might be called the caretaker, or the housekeeper of the body. Without
it your body-house would go to ruin; for the Bible says, “The life of
all flesh is the blood.” After passing through the kitchen, serving
room, and dining room, the blood enters a dark tunnel and comes to your
heart.
HELEN: But what makes it such a bright red color?
MOTHER: Because it has millions of little red bodies called
cor´pus-cles. Really it is a pale yellow, but there are so many of
these tiny folk floating around that they make it look red, just as
a river would if it were packed full of tiny red fishes, or as water
would if you should fill a bottle with very small red beads and then
cover them with water.
PERCY: But are all the cor´pus-cles red?
MOTHER: No; some are white, but there are many more red than white.
AMY: What do they look like?
MOTHER: You can not see them at all unless you should look through a
mi´cro-scope. The red cor´pus-cles are shaped like a little biscuit
with a dimple in the middle. The white ones keep changing their shape
in a very wonderful way. First they are round, then square, then
three-cornered, and they take on ever so many other shapes. There are
several millions of these little red and white fellows in a single drop
of blood.
[Illustration: _Corpuscles._]
ELMER: But you said it went through a dark tunnel to get to the heart.
Please tell us about that.
MOTHER: The tunnel is round, like a tube, and I must tell you that
these tubes are in every part of your body. Some are quite large, some
are small, and some are so tiny that you could not see them if you
should try. They are like a tree with its trunk dividing into large
branches, and these into smaller ones, till at last they become little
twigs. The largest tubes for carrying blood through the body are called
arteries. The smaller ones are called veins. The arteries carry fresh,
bright, clean blood to every part of your body-house. It bounds along
with a hop, skip, and jump, as though it were in a hurry to get to
work. The arteries have very strong walls, and, as I told you, the
blood soon finds itself in the heart.
HELEN: Which room did it go into first?
MOTHER: When the blood is fresh and clean it goes into the top room on
the left side. It keeps coming in until the room is filled full. Then
the little folding doors open, and the blood is crowded into the lower
left room, the doors fly back, and--
AMY: But please tell us about the doors.
MOTHER: They are made so that the blood could not get back into the top
room if it wished; for they never swing but one way, and some small
cords hold them in place. These doors are called valves. When the lower
room is filled, the walls press together, and the blood is forced into
the largest blood tube in the body, the walls of which are so very
smooth, that the blood passes along with a merry bound. The tube keeps
growing smaller the farther we go from the heart, and branches into
many smaller tubes.
PERCY: And how far does the blood go?
MOTHER: Perhaps it first takes a trip through the trunk of your body,
down through your right leg, and on to the end of your big toe. The
tubes at last become very small, and there are so many of them that
they are like a network of the finest lace. A hair would seem like
a big rope beside them. They are so very tiny that you can not see
them. Their walls are thinner than tissue paper, and they are so close
together that you can not touch your skin with the point of a needle
without touching some of them. When the blood comes to these tiny
tubes, it does not travel so fast as at first, and as it passes along,
the muscles pick it to pieces, take the part they want as food, and
load the blood down with waste which they can not use. When they are so
hungry, the blood is glad to feed them and give them the oxygen, which
makes them warm.
AMY: Did it stay long in those little tubes?
MOTHER: No; it went through as quickly as it could, and on its way back
found itself in bigger tubes, which keep growing larger; for it is now
on its way back to the heart. This picture will help you to see the
road it travels. It is now a dark red color, and unfit to work longer
till it is washed. Back it goes to the heart, the tubes through which
it travels growing larger all the way until it tumbles into the right
top room of the heart, which, as you have learned, always has dirty,
worn-out blood in it. But it is not allowed to stay there; for between
this room and the lower right room there are three folding doors kept
in place like the two on the left side, and through them it passes.
The walls of the rooms on the right side of the heart are not as thick
as those on the left side. I think that must be because the left side
sends the blood farther than the right.
[Illustration: Vein, artery and capillary]
HELEN: Does the blood stop to rest in the lower right room?
MOTHER: Oh, no; it never rests as long as there is any life in it! The
heart squeezes it out into another big tube, and it soon finds itself
in the bath room, where it is washed through and through, and its color
becomes as bright red as when new.
AMY: And where does the blood then go?
MOTHER: Straight back to the left side of the heart, where it is pumped
out the same as before; and this time we will say it goes to the
kitchen of the house you live in, and helps the cook get the dinner you
have eaten ready to be made into more blood. The old blood eats some of
the good things, and again it is sent to the right side of the heart
and back through the bath room.
PERCY: And what then?
MOTHER: Its next trip may be taken to the brain, to help a little girl
learn her lessons in school. The brain takes what it can use, and back
the blood goes to the right heart, around through the bath room again,
and the next time it may be sent to the liver, where it finds sugar and
bile-making going on, as usual.
ELMER: But how can the blood be of any use there?
MOTHER: I think you would not ask such a question if you could go there
to see. It “takes all the starch out of it,” as you sometimes say, and
some other things besides, to make into sugar. It also uses part of it
to make into bitter bile, so you may well believe that when it goes
back to the heart there is not much left that is of value. But after a
good wash in the bath room the blood goes back to the heart, and this
time may be sent to the bones in your fingers, and they take what lime
it has. This drop was just making its way back to the heart again when
Amy cut her finger and let it out.
PERCY: But I should have thought the blood would have been worn out
making so many trips.
MOTHER: So it would if it was not made new by the food you eat. It
keeps taking as well as giving as it goes round and round through the
body. You would not expect a housekeeper to keep everything tidy and
clean in a house, and not give her what she needed to make her strong
and able to work; and so the master of the house gives the blood plenty
to eat; and it makes no complaint as long as it can do its work well.
It is a very busy person, we might say, and, as there is no end of
things to do in the house in which you live, the blood works night and
day.
ELMER: But I don’t see how the blood can take with it all that is
needed to mend the different parts of the house.
MOTHER: It is supposed to carry with it a supply of everything that is
needed to keep the house in order as it goes, so that when a bone says,
“I want some lime,” or a muscle says, “Please give me some al-bu´men,”
each part gets what it calls for if it is in the blood. Whether it has
what every part needs depends on what the master of the house sends
into the kitchen to make blood. Have I told you about the filters in
the body?
AMY: I’m sure you have not. Please tell us now.
MOTHER: There are two of them in the lower part of the trunk close
to the back, one on each side. They are the shape of a bean, and are
called the kidneys. The blood passes through them, and some of the
poisons it has picked up are strained out and sent to a storeroom,
called the bladder, where they are kept till the brain gives an order
to send them away.
HELEN: But there is one thing I would like to know. I can see how blood
can run down-hill into our fingers and toes, but I can’t see how it can
climb back up to the heart again. Will you please tell me?
[Illustration: _A kidney._]
MOTHER: The heart is the power that sends it through the arteries to
every part of the body, whether it is up-hill or down. Now when the
blood has come to the end of its journey, and has reached the tiny
hair-like veins of which I told you, more blood keeps coming down and
pushes it on till it starts back through the larger veins. The blood
keeps crowding behind, and the veins are made in such a way as to help
it climb up.
PERCY: But how are they different from the arteries?
MOTHER: Did you ever see little watch-pockets hung in bedrooms in which
to put watches? Well, the veins have tiny pockets in them, as you see
in the picture.
[Illustration: “_Veins have tiny pockets in them._”]
AMY: But I don’t see how that helps the blood in climbing.
MOTHER: It is this way: If you had a tube with little pockets and
should hold it so the top of the pockets was _down_, you could pour
anything through it and they would not stop it from passing. But turn
the tube the other way, with the pockets _up_, as you see in the
picture, and they would catch and hold anything you tried to pour
through the tube. It is the same way with the veins and the blood. If
the blood should try to go back, the pockets would fill full and hold
it, but when it is passing up toward the heart, they let it slip by
without holding it back.
ELMER: Then the blood keeps going round and round in the body, and
never stops.
MOTHER: Yes; and this “going round and round,” as you say, is called
the cir-cu-la´tion. This drop of blood would have kept going until it
was used up in mending your body and helping keep it alive, if it had
not slipped out through the cut in Amy’s finger into the world in which
you live and move.
I know you have all enjoyed hearing how the blood travels through
the body. Let me tell you a little story I read of what a boy said
in school. His teacher asked him to tell the class how the blood
cir´cu-lates, or goes round and round.
“Please, sir,” said the lad, “the blood goes down one leg and up the
other.”
“Very clever of it, I am sure,” said the teacher. “_How does it get
across?_”
Perhaps that was something the boy had not thought of, and I am sure
you would never give such an answer as that since you have heard the
story of a drop of blood. Let us see the cut finger where it came out.
AMY: It doesn’t bleed at all now, mother.
MOTHER: No; and that makes me think to tell you something else about
this wonderful caretaker. If we had a quart of blood and should let it
stand awhile, it would become thick like jelly. But if you should take
a bundle of twigs and keep stirring it round and round, it would not
get thick at all. If you looked at your bundle of twigs after stirring
the blood with it, you would find the twigs covered with a sticky
substance. If you should wash them, you would wash away the red color,
and would have left a soft, stringy mass all matted together.
HELEN: But what is it good for?
MOTHER: It is called fibrin, and if it were not in the blood, you
would bleed to death if you cut yourself. So long as the blood stays
in the body, the fibrin goes quietly with it wherever it goes; but if
it begins to run away, as it did from Amy’s finger, the fibrin goes to
work at once to cork up the place so it can not get out.
PERCY: How long does it take the blood to go from the heart through the
body and back again, mother?
MOTHER: I am sure you will be surprised when I tell you that the heart
sends it with such force that it will go to the farthest part and get
back in from three to eight minutes, and some say it takes even less
time than that.
ELMER: What! so quickly as that! It does not seem possible.
MOTHER: And though one-eighth of the body is blood, yet it will _all_
pass through the heart in about the same time.
HELEN: How wonderful! But I don’t see how all these little things in
the blood, called cor´pus-cles, can get through the tiny, hair-like
veins, which are so small.
MOTHER: We can learn a useful lesson from them, and you would be
pleased, I know, to watch them, if they were only large enough so you
could. They seem to know just what they want to do, and where they
ought to go. When the little veins are too small for more than one to
go in at a time, they do not push or crowd one another. One row waits
as politely as can be till the others have passed in, and then they
follow. How wonderful it is to think of this river of life flowing
round and round, and we feel nothing of it but the gentle tap, tap
of the heart as it sends it bounding through every part of the body!
Should it stop, we would die; for “the blood is the life.”
PERCY: But how did people find out that the blood goes around as it
does?
MOTHER: A doctor in England, named Harvey, first discovered it. Before
his time people thought air went around through the body in the
arteries. Men have studied the subject since Dr. Harvey lived, and they
keep learning more about it all the time.
AMY: Does water go into the blood, mother?
MOTHER: Yes; it very quickly finds its way there, and it is the same
with strong drinks, such as beer and whisky. It only takes a very few
minutes for anything we drink to get into the blood stream.
The walls of the veins and arteries are governed by the nerves of our
telephone system. They let just the right amount of blood flow through
them all the time. When alcohol gets into the blood, it puts the
nerves to sleep, and so too much blood goes into the little veins. You
know a man who drinks has a red face. If he drinks a long time, his
nose gets so red that it is called a “rum blossom.” This is because so
much blood goes to his nose that it becomes large and red. Alcohol also
makes the walls of the arteries weak, so they sometimes burst open and
the person dies.
Now that we have learned a few things about the blood, we must be
careful what we give this care-taker of the body to eat. We have
learned very little of what there is to know, and as you grow older I
hope you will study and learn more.
THE BATHROOM
HELEN: I have been thinking of what you said about the blood being
washed every time it made a trip to any part of the body. Where is the
bath room in the body-house, mother?
MOTHER: It is a large double room, and it is found in the top part of
the trunk, each side of the heart.
PERCY: Why, I thought that was where the lungs are.
MOTHER: So it is; and it is in them that the blood is made clean after
every journey it takes through the body.
AMY: But is there water in the lungs in which to wash the blood?
MOTHER: No; and the blood could not be washed in water if there was.
It takes air to wash blood. Let us try to learn how it is done; but
first we will take a peep into the bath room. There are two ways to
get in. One is through the folding doors, the way that our food goes
to the kitchen; for you remember there are four or five doors back of
the pink curtain. In this place the air finds a door standing wide
open, and it passes through a passage, called the windpipe, which is
about three-fourths of an inch wide, and about four and one-half inches
long in grown people. After going through the windpipe it comes to two
passages, leading to the two parts of the bath room. While we might
call it a double bath room, yet it is really two rooms.
ELMER: That must be the right and left lungs.
[Illustration: _The lungs._]
MOTHER: That is right. But I must not forget to tell you that there is
another way to reach the lungs, and that is through two little doors,
always standing open, just above the folding doors which lead to the
kitchen. The air finds a long, curved passage to go through, and this
is much the better way to go, because if it goes in cold, it passes
some places where it gets warm before reaching the bath room. You know
it would be rather hard to wash clothes in cold water, and so it is
much better to have warm than cold air in which to cleanse the blood.
HELEN: You mean it passes through the nostrils in the nose.
MOTHER: Yes; and another reason why this is the best way for it to go
is because the air is filtered or strained through some little hairs,
which do their best to keep any dirt or dust which may be in the air
from going further. These passages open back of the pink curtain, and
it goes down through the windpipe the same as though it had passed
through the mouth.
PERCY: But I should think our food would go into the bath room instead
of the kitchen.
MOTHER: It would, only that, as soon as it starts for the kitchen,
there is a little trap-door which feels it coming, and it shuts down
quickly over the air passage, so nothing can get through. Suppose the
trap-door does not do its duty quickly enough, and food “goes the wrong
way,” as we sometimes say, the person chokes and has a bad time till
the food is out of the way. I once saw a fowl eating corn, and in some
way a kernel got into her windpipe. She began hopping about in great
distress, and died as quickly as though her head had been cut off. It
sometimes happens that people are choked to death in the same way.
HELEN: But how does the bath room look?
MOTHER: It is a pretty pink color and seems much like a very fine
sponge. If we could go inside we should find the passages divided again
and again, till there are thousands and thousands of tiny air tubes,
each ending in a little pouch quite like a bunch of grapes, only you
should think of the grapes as being as small as a grain of sand. When
the lungs are full of air, they grow larger, and when we breathe it
out, they grow small.
ELMER: That is like a pair of bellows.
[Illustration: _A pair of bellows._]
MOTHER: Very much the same, and the bellows will help us understand
how we breathe. Try to think of a little tree with its trunk, limbs,
and leaves all hollow. If air were blown through the trunk, it would
make every leaf puff out, and when no air was blown in, they would fall
together again. It is the same with our lungs. They keep swelling out
and falling together about eighteen times every minute.
AMY: But how is the blood washed in air, mother?