A Handbook of Health - Woods Hutchinson (whitelam books txt) 📗

you could prick or burn the sole of your foot as much as you pleased, and you would not feel any pain at all.

As soon as the surface of the brain has recognized the pain and where it comes from, it promptly sends a return message back down the same cable, though by different nerve-wires, to the muscles of the foot and leg, saying, "Jerk that foot away!" As a matter of fact, this message will arrive too late, for the centres in the spinal cord will already have attended to this part of the matter, often almost before you know that you are hurt.

However, there is plenty of other work for the brain to do; and its next step, quicker than you can think, is to wake up a dozen muscles all over the body with the order, "Sit down!" And you promptly sit down. At the same time, the brain "central" has ordered the muscles of your arms and hands to reach down and pick up the foot, partly to protect it from any further scratch, and partly to pull the thorn out of it. Next it rushes a hurry call to the muscles controlling your lungs and throat, and says, "Howl!" and you howl accordingly. Another jab at the switchboard, and the eyes are called up and ordered to weep, while at the same time the muscles of the trunk of your body are set in rhythmic movement by another message, and you rock yourself backward and forward.

This weeping and rocking yourself backward and forward and nursing your foot seem rather foolish,—indeed you have perhaps often been told that they are both foolish and babyish,—but, as you say, you "can't help it," and there is a good reason for it. The howl is a call for help; and if the hurt were due to the bite of a wolf or a bear, or the cut had gone deep enough to open an artery, this dreadfully unmusical noise might be the means of saving your life; while the rocking backward and forward and jerking yourself about would also send a message that you needed help, supposing you were so badly hurt that you couldn't call out, to anyone who happened to be within sight of you. So that it isn't entirely babyish and foolish to howl and squirm about when you are hurt—though it is manly to keep both within reasonable limits.

If the message about the thorn had been brought by your eyes,—in other words, if you had seen it before you stepped on it,—then a similar but much simpler and less painful reflex would have been carried out. The image of the thorn would fall on the retina of the eye and through its optic nerve the message would be flashed to the brain: "There is something slim and sharp in the path,—looks like a thorn." When this message reached the brain, and not till then, would you see the thorn, just as in the case of the pain message from the foot. Then the brain would take charge of the situation just as before, flashing a hasty message to the muscles of the legs, saying, "Jump!" while its message to the throat and lungs, instead of "Yell," would be merely, "Say, 'Goodness!' or 'Whew!'" and you would say it and run on.

If the thing in the grass, instead of a thorn, happened to be a snake, and you heard it rustle, then the warning message would come through your ears to the brain, and you would jump just the same; though, as it is not so easy to tell by a hearing message exactly where the sound is coming from, you might possibly jump in the wrong direction and land on top of the danger.

This is the way in which you see, hear, and form ideas of things. Your eye telegraphs to the brain the colors; your ear, the sounds; and your nose, the smells of the particular object; and then your brain puts these all together and compares them with its records of things that it has seen before, which looked, or sounded, or smelt like that, and decides what it is; and you say you see an apple, or you hear a rooster crow, or you smell pies baking. Remember that, strange as it may seem, you don't see an orange, for instance, but only a circular patch of yellowness, which, when you had seen it before, and felt of it with your hand, you found to be associated with a feeling of roundness and solidness; and when you lifted it toward your nose, with the well-known smell of orange-peel; so you called it an orange. If the yellow patch were hard, instead of elastic, to the touch, and didn't have any aromatic smell when you brought it up to your nose, you would probably say it was a gourd, or an apple, or perhaps a yellow croquet ball. This is the way in which, we say, our senses may "deceive" us, and is one of the reasons why three different people who have seen something happen will often differ so much in their accounts of it.

It is not so much that our senses deceive us, but that we draw the wrong conclusions from the sights, sounds, and smells that they report to our brains, usually from being in too great a hurry and not looking carefully enough, or not waiting to check up what we see by touching, hearing, or tasting the thing that we look at.

This message-and-answer system runs all through our body. For instance, if we run fast, then the muscle cells in our legs burn up a good deal of sugar-fuel, and throw the waste gas, or smoke, into the blood. This is pumped by the heart all over the body, in a few seconds. When this carbon dioxid reaches the breathing centre in the medulla, it stirs it up to send promptly a message to the lungs to breathe faster and deeper, while, at the same time, it calls upon the circulation centre close to it, to stir up the heart and make it beat harder and faster, so as to give the muscles more blood to work with. If some poisonous or very irritating food is swallowed, as soon as it begins to hurt the cells lining the stomach, these promptly telegraph to the vomiting centre in the brain, we begin to feel "sick at the stomach," the brain sends the necessary directions to the great muscles of the abdomen and the diaphragm, they squeeze down upon the stomach, and its contents are promptly pumped back up the gullet and out through the mouth, thus throwing up the poisons.

And so on all over the body—every tiniest region or organ in the body, every square inch of the skin, has its special wire connecting it with the great telephone exchange, enabling it to report danger, and to call for help or assistance the moment it needs it.

CHAPTER XXI THE HYGIENE OF BONES, NERVES, AND MUSCLES HOW TO GET AND KEEP A GOOD FIGURE

Erect Position is the Result of Vigorous Health. Naturally and properly, an erect, graceful figure and a good carriage have always been keenly desired; and much attention has been paid to the best means of acquiring them; as we say, we try to "get the habit" of carrying ourselves straight and well. But it must be remembered that an erect figure and a good carriage are the results of health and vigor, rather than the cause of them.

Stooping, round shoulders, sitting "all hunched up," or a shuffling gait, are owing partly to bad habits, or "slouchiness," but chiefly to weak muscles and a badly-fed nervous system, often due to a poor digestion and a weak circulation. If a child is not healthy and vigorous, then no amount of drilling or reminders to "sit straight" and "stand erect" will make him do so.

It is of great importance that the child should take an erect and correct position for reading and writing, and while sitting at his desk; and that the desk and the seat should fit him. But it is more important that he should not sit at his desk in a stuffy room long enough to be harmed by a cramped position.

There are few children who will "hump over" at their desks, if the muscles of their backs and necks are strong and vigorous, and their brains well ventilated. Nor will many of them bore their noses into their books, or sprawl all over their copy books when they write, unless the light is poor, or they have some defect of the eyes which has not been corrected by proper glasses. A bad position or a bad carriage in a child is a sign of ill health, and should be treated by the removal of its cause.

Curvatures—Their Cause and Cure. There are various forms of curvatures, or bendings, of the spine which are supposed to be owing to faulty positions of sitting or of carrying the body. There is wide difference of opinions as to their cause; but this all are agreed on, that they practically never occur in sturdy, well-grown, active children; and the way that they are now corrected is by careful systems of balancing, muscular exercise, open-air life, and abundant feeding, instead of using steel braces, or jackets, or schoolroom drills.