Part 19

Under ordinary conditions the heart beats are controlled by certain nerve cells which are located within the heart itself, and these cause the heart to beat even while the brain is asleep. This explains why the heart beats when the brain is asleep, and the fact that the brain when asleep does not exercise its functions, shows how necessary this arrangement and the control of ordinary heart beats is. If this were not so, we should not be able to live while asleep. It is just like the management of a great business in this sense. The general manager of a great business has control of the entire works, but there are occasions when he must be thinking of only one thing in connection with the business, and so he must have his organization so complete, that the parts which he cannot be thinking about at the time will do their work just the same. So he surrounds himself with competent assistants, who look after certain departments while he is busy or away or asleep, and if anything goes wrong while he is away, he calls on special forces to set things right. Now, the brain is the general manager of the whole body and has these nerve cells in the heart as a sort of assistant manager to look after the heart beats in ordinary conditions, and to keep the heart going while he is asleep. But, by reason of his office as general manager, the brain has a special way of sending orders to the heart through special nerves which run from the brain down each side of the neck to the heart. There are two pairs of these special nerves. One pair, if set in motion, will make the heart beat faster, and the other pair will make the heart beat more slowly.

Why Do Our Hearts Beat Faster When We Are Running?

When you start running, the brain knows at once that your legs and other parts of the body will need more blood to keep them going, and so the brain sends down orders through his special nerves which make the heart beat faster, to get busy, and they do. Then when you stop running, your heart is beating faster than necessary--there is really an oversupply of blood being pumped through your system for the time being, and that makes you uncomfortable, until the brain sends word through the other set of nerves to the heart to slow down the heart beat. It is better to stop running gradually, to give the heart a chance to get back to its normal beat gradually also.

Why Do I Get Out of Breath When Running?

This is also caused by your brain in its efforts to keep up your supply of good blood. We breathe to take air into the lungs, where the blood which has once been through the arteries and comes back on its return trip to the heart, is exposed to the air in the lungs, before going back into the heart. The air which we take into our lungs purifies the once used blood and makes it into good blood again. When you run the heart pumps blood into your arteries faster to enable you to run. Thus also, the arteries send much more blood back to the heart through the veins, and this must be purified by the lungs before going back into the heart. To attend to purifying this extra amount of spoiled blood the lungs need more air, and thus you are made to breathe in more air for the purpose. Unless you are in good training--your wind in good condition as we say--it is almost impossible for you to supply the lungs with enough air for the purpose, but whether you can do it or not, the lungs call upon you for more air, and cause you to try to get it, and that is what makes you get out of breath.

Why Does My Heart Beat Faster When I Am Scared?

The natural tendency of a scared creature is to run or fly. The effect of being scared has the same effect on the brain that your starting to run has. The brain is always as quick as you are, and knowing that when you are scared your actual or natural inclination is to run, it is merely getting you in shape so that you can move or run fast.

Why Does Cold Make Our Hands Blue?

Your hands appear blue when cold because the veins which are near the surface are filled with impure blood which is purplish in color. Your hands become cold because there is not sufficient circulation of warm red blood going on to keep them warm. The blood in circulating through your body sends warm red blood through the arteries, and this is returned to the heart through the lungs by way of the veins. The veins carry only used-up blood or what is left of the good red blood when the arteries are through with it. Its color is a purplish blue.

When your hands are blue it means that circulation of good red blood has practically stopped--the red blood is not flowing from the heart through the arteries in sufficient quantity and there is no color in the arteries, as the blood from the arteries has practically all gone into the veins. The veins are full to purplish blue blood, and this makes the hands look blue, because there are a great many veins in the hands close to the surface.

Why Do I Get Red in the Face?

Now, when you rub your cold blue hands together, you start the circulation going again, and that brings the red blood into the arteries, giving you the healthy red color again. When you run hard to get red in the face because you are causing an unusual amount of red blood to flow through your whole body by your violent exercise. Some people with an extraordinary amount of circulation are red in the face all the time. This is because of the presence of a great deal of blood in the arteries, or because the walls of their arteries are so much thinner than others that the red blood shows through more easily.

Is Yawning Infectious?

Yawning is infectious to the extent that other habits are. The desire to yawn which comes to us when we see some one else does so comes under the heading of suggestion. The power of suggestion is greater than many of us realize. We are great imitators of each other. When one of us is downhearted, we are apt to become happy and glad simply by being with other people who are happy and glad. If enough people one at a time tell a perfectly well man that he looks sick, he will actually feel ill, provided he does not suspect a game is being played on him. So a good actor carries his audience with him. He can make them laugh or cry almost at will, and if he yawns, his audience will begin yawning.

Often, however, there is no acting connected with the yawning of the first person. Then the yawn is caused because the person is not sending enough good air into the lungs for purifying the blood, and the yawn is only nature’s way of making us take an exceptionally deep breath of air in at one time. This lack of sufficient good air in the lungs may not be due to the poor breathing, but to the amount of bad air in the room. In such cases it is quite likely that other people in the room yawn when one of them starts it because they all begin to feel the need of more good air at about the same time.

What Makes Me Want to Stretch?

The necessity or desire to stretch comes to us because certain parts of the body are not receiving the proper amount of blood circulation and it is these parts that we stretch at such times. If you have ever been to a ball game, you know, of course, that it has become customary for the crowd, no matter how large, to stretch its legs and arms during the last half of the seventh inning. In fact, that has come to be a fixture at ball games and is universally known as the “stretch inning.” Now, it is not so much the result of a desire to encourage the home team as the natural following out of nature’s laws that originally started this practice. The end of the seventh inning at a ball game generally means that the crowd has been sitting quite still for the greater part of an hour and a half, just long enough for the circulation to become poor in parts of the body, and the custom of stretching at a ball game thus comes from the necessity of getting a little more speed into the action of the heart to increase the blood supply.

In other words, the stretching constitutes a mild form of exercise. You will notice the ball players themselves do not stretch themselves in the last half of the seventh inning. They are getting enough exercise without that.

It is natural, however, for us to stretch as we wake up from sleep after having lain quietly in one position for one or more hours. It is nature’s way of causing the heart to work faster.

What Happens When I Stretch?

What happens is simply this. When you stretch your arms and legs, you squeeze the arteries and veins which are a part of your arms and legs, much as happens when you pull on a piece of rubber tubing. The tubing becomes flat instead of perfectly round, and it is not so easy to send water through a flat tube as through a round one. Just so with the heart. It is the heart’s business to send blood through the arteries at all times, and when you make them flat the heart’s job becomes just a little harder, and it goes to work beating just a little faster to overcome this extra difficulty. By that time you are through stretching and the heart is busy pumping blood a little faster than ordinarily, and that is what makes you feel so good after you have stretched.

Why Can We Think of Only One Thing at a Time?

If you are asking the question intelligently, you must know that to think means to concentrate, and in that sense we can only think of one thing at a time, because it takes all of that part of the brain which is used for thinking for just one thing. To give close attention to any one subject means to turn the entire brain force practically in one direction. To let other things pass through the mind at the same time may appear not to interfere with the one thought, but they do, and our conclusions suffer accordingly.

You can be doing something with one part of your body, while engaged in thinking of one thing, but only such things as are more or less mechanical as the result of habit, such as walking, or moving the arms--things which the parts have done so often that actual attention by the brain is not absolutely essential. Take for instance, the fact that a man in deep thought on one subject will sometimes walk up and down the room or along the sidewalk. He can do this walking and still think concentratedly, but if he stubs his toe on the leg of a chair or on a rough place in the walk, his thought is broken, because the brain immediately takes itself out of the thought and pays its attention to the toe that was stubbed.

Why Do I Turn White When Scared?

Simply because, when you are scared or frightened, the blood almost leaves your face entirely. Under normal conditions, the red blood which is flowing through the arteries of your face, gives the face a reddish tinge, and your face becomes white when you are frightened, because then the blood leaves the face. It is quite singular, but when you are really frightened, whatever the cause may be, the human system receives such a shock that the heart just about stops beating all together. When your heart stops beating of course the flow of the blood from the heart stops and then there is no supply of fresh red blood coming through the arteries under the skin of your face. Therefore you look white--the color your face would be if no blood ever flowed through your arteries and veins. Some people have faces so white they look as though they were scared all the time. This is not because they have no blood flowing through the veins and arteries in their faces, but because their supply of blood is less than other peoples, and sometimes because the walls of their arteries and veins are much thicker than the average that the color of the blood does not show through. There are also many people who have so much blood in their systems all the time, and the walls of whose arteries are so thin, that they look at all times as though they might be blushing.

What Makes Me Blush?

Anything that will make your heart send an extra supply of blood into the arteries and veins which supply your face with blood, will make you blush. Embarrassment will do this. So will anger generally, although sometimes people get so angry that the blood is driven out of their faces. In this case they are so angry that their heart has stopped beating, practically.

What Occurs When We Think?

When we think the mind is acting on sensations; it is receiving, in conjunction with memories of sensations it has previously received. Sensations as they reach the mind arouse the mind to activity and, as soon as the sensation is received, the mind begins to compare the new sensation with sensations received at previous times, and by putting things together reaches a conclusion.

When you are thinking you are really trying to call upon memory to help you. You know the thought of one thing calls up another, and this leads to something else. This association of ideas is the faculty which enables us to think consecutively and accurately. It is the business of the mind to receive the sensations that enter it and arrange them in their proper places. That memory of past sensations is the important part of thinking, is proven by the fact that when we have forgotten a thing we are unable to think what it was.

Can Animals Think?

For this reason if animals have memory they should be able to think. It is now believed that many animals have to a certain extent the power to remember.

A dog will recognize his master even though he has not seen him for years. We might think he does this by his highly developed power of smell, but if his master has come from a direction opposite to that from which the dog first sees him, he could not have tracked him by his smell. A dog will recognize his master from quite a distance, so he must have to a certain extent the ability to remember or the power of association of ideas, which amounts to the same thing. Again, a horse that once belonged to the fire department, even though now hitched to a milk wagon, will have the impulse to run to the fire when he hears the fire gong. And an old war horse will prick up his ears as he used to when he hears the bugle call.

Why Do I Sneeze?

You sneeze sometimes when you look up at the sun or at a bright light. There does not seem to be any real good explanation of why looking at a bright light should make you sneeze. It is due to the connection there is between the nerves of the eyes and the nose. You generally blink if you look at a bright light suddenly, and the blinking process stirs the nerves inside of the nose to make you sneeze.

You know, of course, that the start of the sneeze is inside of your nose. The nose is, besides being the organ of smell, the channel through which we take air into the lungs, when we breathe properly. The nose is lined with membranes, back of which are a net of very small nerves which are extremely sensitive. The membranes are placed there to catch and hold the impure particles of matter which come into the nose when we take in a breath of air, and sneezing is only one effective way of cleaning out the nose. It is brought on only when some particularly difficult job of nose-cleaning has to be done. Pepper up the nose will make you sneeze quickly, because pepper produces a very great irritation inside the nose, and the nose goes to work at once to get rid of it in the quickest possible manner as soon as the pepper comes in. Other things have the same effect. Sometimes a cold in the head causes you to sneeze. The sneeze in that event is merely nature’s effort to clean out the nose when other efforts have failed.

There are many suggestions for stopping a sneeze before it takes place, after you feel it coming on, such as putting the finger on each side of the nose, and many others. But a half sneeze does not remove the cause of the sneeze, so it is much better to sneeze it out, and many people enjoy the after effects of sneezing so much that they take snuff into the nose to produce it.

What Happens When I Swallow?

The muscles of your throat act in the form of a ring when food passes into your throat. The food does not drop directly into your stomach. In other words, the action is not quite the same as when you drop a stone out of the window. When you do the latter, the stone hits the sidewalk or whatever is below at the time, with a smash. It would hardly do to have our food drop into the stomach, so the muscles of the throat are arranged to contract in rings which push or squeeze the food downward, and the food is passed from one ring of muscles to the other. It is just like pushing a ball down into the foot of a stocking that is apparently too small for it to drop down. You put the ball in the top of the stocking and then by making a ring of your fingers around the stocking you can push the ball down. When you swallow, you start the muscles of your throat to making these rings. The upper ring squeezes the food on to the ring below it and so on down to the stomach.

What Makes the Lump Come In My Throat When I Cry?

The “lump” which comes up into your throat when you cry is caused by a sort of paralysis of the rings of muscles in your throat. The muscles of your throat can make these rings or waves upward also, but it is more difficult upward than downward--probably because of lack of practice, as we say. When you have put something into your stomach that makes you sick and causes you to vomit, the throat muscles take the matter from your stomach and bring it back to the mouth in the same way, except, of course, that this action begins at the bottom.

Sometimes when you cry, or lose control of yourself in some other way (you know, of course, that in crying you always lose control of yourself, don’t you) practically the same effect is produced as when you have something in your stomach that should come out. Crying, or the thing that happens sometimes when we cry, makes the throat muscles act just as if we were vomiting, and as the action is an unnatural one, when the ring or wave reaches the top of the throat, we feel the lump or ball as we call it. We feel the lump because the throat has been made to go through the motion of eliminating something in an unnatural way, just as your arm will hurt if you pretend to have a ball or a stone in it, and in throwing the imaginary ball or stone, you put the same force into your movements as you would if you had an actual ball or stone in your hand and were seeing how far you could throw it.

Why Do We Stop Growing?

We eventually stop growing because certain of the cells of the body lose their ability of increasing in size and producing other cells. It is one of the marvels of the construction of the human body that this is so and one of the wisest provisions also. At first the cells of the body crave lots of food and increase in size, divide and then the parts go on growing until they become of a certain size, when they again divide and each part goes on growing, etc., and thus we grow. A growing boy needs more fond than a mature man, because he needs some of it to grow with, while the man only has to keep what growth he has going, i. e., alive.

We say this limit of growth is a wise provision of nature because if there were no limit to the size we might become, we would not know how large to build houses, barns, etc., or else we would have to build them so large to start with that we would be lost in them for a long time. We would constantly be forced to change these things and there would be no basis to reckon from. Dogs might be as big as elephants and then they would be of no use to us, or of what use would a dog as big as an elephant be to a boy of five years. You see it would not do at all to have this rule changed.

Why Do We Grow Aged?

We age directly in accordance with the lives we lead. You can bend a wire back and forth a number of times at the same point without breaking it, but eventually it will break. Just so with the human body. You can use each part of it for its own purposes a number of times, but eventually the break will come. Or, you can fail to make a part of it perform its regular functions, and it will die--the break will come. The human body is the most wonderful machine in the world, but even it will eventually wear out. Every time you move your arm, leg or some other part of your body, you destroy some tissues. The body replenishes and builds up those tissues again for a certain time. When you bend a joint in your body, the body oils the joint naturally, but as you grow older, or rather, as you use the different parts of your body more and more, it brings nearer always the time, when the body cannot, of its own accord, build up again the tissues you have destroyed. That is why some people become very old at forty and others are still comparatively young at seventy. It requires a great deal of care and attention and the elimination of all abuse of the body to keep us young when we are old. The use of drink, lack of sufficient sleep and other abuses prevent the body from restoring the tissues which have been destroyed. Worry and sorrow age us very rapidly, because these things affect the nerves. If the nerves are not quiet we cannot get any rest and without rest we grow old very rapidly.

What Causes Wrinkles?

Wrinkles come to us in several ways. An easy way to cause wrinkles is to scowl and frown and get into the habit of doing this. When you scowl or frown you pucker up the skin on your forehead into wrinkles and if you continue the habit the skin on your forehead makes the wrinkles permanent. You have given your skin the wrinkle habit. This acts just the same way as your arm would, if you tied it up in a sling and held it close to your side for a very long time--a number of weeks. When you took the sling off you would find your arm useless--a dead arm. It had developed the habit of doing nothing.

In old people, however, wrinkles come more naturally. There it is the case of the skin not receiving the proper nourishment and attention to keep the circulation of the blood right. When people become old they are apt to lose the fat which has accumulated under their skins. If they had taken just the right amount of exercise all of their lives and kept their circulation perfect in all parts of the body, there would have been no fat there. But when the fat accumulates, it makes the skin grow larger, and then when the fat disappears and people get thin again, the skin is too large and makes the wrinkles.

Does Thunder Sour Milk?

Milk will sour in any kind of warm and moist temperature and, because just before and during a thunderstorm the air is generally quite warm and moist, it is only natural that it should turn sour. It is wrong, however, to say or think that thunder makes milk sour. Thunder is only a noise and noise cannot do anything but make itself heard. The fact that it is generally warm and moist, however, when it thunders, coupled with the fact that these conditions of the air sour milk very rapidly, have led people to connect the two in their minds and caused them to fall into the error of believing that the thunder is responsible for the change in the milk.

What Makes the Rings in the Water When I Throw a Stone Into It?

Every movement has a beginning. When a movement on the earth is once started it keeps on going until something stops it. If nothing stops it it will go on forever.

When you shout you start air waves going in every direction, which keeps on going until stopped by something which has the power to break up their waves.

When you throw a stone into the ocean you start a series of ripples or waves which spread out in every direction and if you dropped your stone into the exact middle of the ocean--half way from each side--in a perfectly calm sea undisturbed by other forces, your ring of ripples would go on getting larger until it landed on the beach or shore on each side of the ocean at the exactly the same time and there the beach or shore would stop it.