A Handbook of Health Part 22

Here comes in one of the most curious things about this ingenious hearing-apparatus. This little hollow behind the drum-skin has to be kept full of air in order to let the drum vibrate properly, and this is arranged for by a little tube (the Eustachian tube) which runs down from the bottom of it and opens into the back of the throat just behind the nasal pa.s.sages, and above the soft palate. When you blow your nose very hard, you will sometimes feel one of your ears go "pop"; and that means that you have blown a bubble of air out through this tube into your drum cavity.

If your nose and throat become inflamed, then the mouth of this little tube may become blocked up; the drum can no longer thrill, or vibrate, properly; and, for the time being, you are deaf. This tube is of great importance, because nearly all the diseases that attack the ear start in at the throat and travel up the tube until they reach the drum cavity.

This is why one so often has earache after an attack of the grip or after a bad cold. The drum cavity, with its chain of bones and its tube down to the throat, is called, from its position, the _middle ear_.

The _outer_, or _external, ear_, though far the largest of the three parts, and quite imposing in appearance, is really of little use or importance. It is simply a sort of receiving trumpet for catching sounds, with a very wide and curiously curved and crumpled mouth, or bell. The large, expanded mouth of the trumpet, called the _concha_ ("conch sh.e.l.l"), was at one time capable of being "p.r.i.c.ked up" and turned in the direction of sounds, just as horses' or dogs' ears are now; and in our own ears there are still for this purpose three pairs of tiny unused muscles running from them to the side of the head. But the concha is now motionless and almost useless, except for its beauty; and it is very troublesome to wash.

The Care of the Ear. The tube of the trumpet leading down from the surface of the ear to the drum is lined with skin; and this skin is supplied with glands, which pour out a sticky, yellowish fluid called _ear wax_, which catches the bits of dust or insects that get into the ear and, flowing slowly outward, carries them with it. If it is let alone, it will keep the ear ca.n.a.l clean and healthy; but some people imagine that, because it looks yellowish, it must be dirt; and consequently, from mistaken ideas of cleanliness, they work at it with the end of the finger, the corner of a towel, or even with a hairpin, an ear-spoon, or an ear-pick, and in this way stop the proper flow of the wax and make it dry and block up the ear.

Remember, you should not wash too deeply into your ears; (as the old German proverb puts it, "Never pick your ear with anything smaller than your elbow"). And if you don't, you will seldom have trouble with wax in the ear. Scarcely one case of deafness in a hundred is caused by wax.

When your ear does become blocked up with wax, it is best to go to a doctor and let him syringe it out. Picking at it, or even syringing too hard, may do serious damage to the ear.

If an earache is neglected, the inflammation may spread into some air-cells in the bony lump behind the ear (the _mastoid_) and thus cause _mastoid disease_, which may spread to, and attack, the brain if not cured by a surgical operation.

OUR SPIRIT-LEVELS

The Sixth Sense. Though we usually speak of having five senses,--sight, smell, hearing, touch, and taste,--we really have also a sixth--the sense of direction, or of balance. The "machine" of this sense is comparatively simple, being made up of three tiny curved tubes, which, from their shape, are called the _semi-circular ca.n.a.ls_. These are buried in the same bone of the skull as the internal ear, and so close to it that they were at one time described as part of it.

These little ca.n.a.ls are three in number, one for each of the dimensions--length, breadth, and thickness,--so that whichever way the head or body is moved,--backward and forward, up and down, or from side to side,--the fluid with which they are filled will change its level in one of them, just as the "bead" does in the carpenter's spirit-level that you can find in any tool shop. The delicate nerve twigs that run out into the fluid in these tiny ca.n.a.ls are gathered together into a bundle, or nerve-cable, which runs back to the part of the brain known as the _cerebellum_ or hind-brain, which has most to do with controlling the balance and movements of our bodies.

It is the disturbance set up in these spirit-level ca.n.a.ls by the pitching and rolling of a s.h.i.+p, which makes us seasick. Neither the stomach, nor anything that we may have eaten, has anything to do with it. In the same way we sometimes become sick and dizzy from swinging too long or too high, or from riding on the cars.

FOOTNOTES:

[28] To show in how many different ways nature may carry out the same purpose, the smelling organs in insects, lobsters, and crabs are on the ends and sides of tiny feelers, which they wave about; and the eyes in lobsters, crawfish, and snails, are on the ends of stalks, which they thrust about in all directions as a burglar handles a bull's-eye lantern. Snakes "hear," or catch the sound-waves, with their flickering, forked tongues; and gra.s.shoppers and locusts have "ear-drums" on the sides of their chests.

[29] These are called the _recti_ or "straight" muscles, upper, lower, inner, and outer, according to their position. Then, to roll the eye round and round, there are two little muscles, one above and one below, which run "crosswise" of the orbit, called the upper and lower _oblique_ muscles.

[30] The retina is chiefly made up of a great number of fine little nerve cells called, from their shape, the _rods_ and _cones_. These are kept soaked in a colored fluid called the _retinal purple_, which changes under the influence of light, somewhat in the same way that the film on a photographic plate does, thus forming pictures, which are translated by the rods and cones and telegraphed along the fibres of the optic nerve to the brain. Naturally, all parts of the retina are not equally sensitive to light; its centre, which is directly opposite the pupil of the eye, is far the most so, while those around the rim of the cup are dull. This is why, when you are looking, say at some one's face across the room, only the face and a few inches around it are seen perfectly clear and sharp, while the rest of the room is seen only vaguely.

[31] As the inside of the eye is dark, or comparatively so, the pupil, or little opening in the centre of the iris, looks black, and was at one time supposed to be a solid body instead of a hole. You can easily watch the pupil changing in size, according to the brightness of the light, from a mere pin-point in very bright sunlight or gaslight, up to the size of the b.u.t.t-end of a lead pencil in the dark or in a dim light.

This change in size is very simply but ingeniously carried out by two sets of tiny muscles. One set of these muscles runs in a ring right around the pupil; and when they shorten, the opening is contracted or narrowed. The other set runs outward through the iris like the spokes of a wheel; and when they shorten, they pull the pupil open. If anyone has had "drops" (_atropin_) put into his eyes in order to have them fitted with gla.s.ses, he will know what a disagreeably dazzling thing it is to have the pupil permanently enlarged, so that it cannot _contract_ in a bright light.

CHAPTER XXIV

THE SPEECH ORGANS

The Voice, a Waste Product. It is one of the most curious things in this body of ours that what we regard as its most wonderful power and gift, the voice, is, in one sense, a waste product. So ingenious is nature that she has actually made that marvelous musical instrument--the human voice--with its range, its flexibility, and its powers of expression, out of spent breath, or used-up air, which has done its work in the lungs and is being driven off to get rid of it. It is like using the waste from a kitchen sink to turn a mill.

The organs that make the human voice were never built for that purpose in the first place. Unlike the eye and the ear, nature built no special organ for the voice alone, but simply utilized the windpipe and lung-bellows, the swallowing parts of the food pa.s.sage (tongue, lips, and palate) and the nose, for that purpose, long after they had taken their own particular shapes for their own special ends.

The important point about this is that a good voice requires not merely a large and well-developed "music box" in the windpipe, but good lungs, a well-shaped healthy throat, properly arched jaws,--which mean good, sound teeth,--clear and healthy nasal pa.s.sages, and a flexible elastic tongue. Of course, the blood and the nerves supplying all these structures must be in good condition, as well. So practically, a good voice requires that the whole body should be healthy; and whatever we do to improve the condition of our nose, our teeth, our throat, our lungs, our digestion, and our circulation will help to improve the possibilities of our voice. There are, of course, many exceptions; but you will generally find that great singers have not only splendid lungs and large vocal cords, but good hearts, vigorous const.i.tutions, and bodies above the average in both stature and strength.

How the Voice is Produced. The chief parts of the breathing machine that nature has made over for talking purposes are the windpipe, or air tube, and the muscles in its walls. In the neck, about three inches above the collar bone, four or five of the rings of cartilage, or gristle,--which, you remember, give stiffening to the windpipe,--have grown together and enlarged to form a voice box, or _larynx_.

[Ill.u.s.tration: THE VOCAL CORDS

Looked at from above: position _A_, in quiet inspiration; _B_, in singing a low tone; _C_, in singing a high tone.]

The upper edge of this voice box forms the projection in the front of the throat known by the rather absurd name of the "Adam's apple." This grows larger in proportion to the heaviness of the sounds to be made, and hence is larger in men than in women and boys. When the boy's voice box begins to grow to the man's in shape and size, his voice is likely to "break"; for it is changing from the high, clear boy's voice to the heavy, deep voice of the man.

Inside of this voice box, one of the rings of muscle that run around the windpipe has stretched into a pair of straight, elastic bands, or strings, one on each side of the air pipe, known as the _vocal cords_, or voice bands. These are so arranged that they can be stretched and relaxed by little muscles; and, when thrown into vibration by the air rus.h.i.+ng through the voice box, they produce the sounds that we call talking or singing. The more tightly they are stretched, the higher and shriller are the tones they produce; and the more they are slackened, or relaxed, the deeper and more rumbling are the tones.

This is why, when you try to sing a high note, you can feel something tightening and straining in your throat, until finally you can stretch it no tighter, and your voice "breaks," as you say, into a scream or cry.

All musical instruments that have strings, are played, or produce their sounds, upon this same principle. The thinner and shorter the string, or the more tightly it is stretched, the higher the note; the heavier and longer the string, the lower the note. But no musical instrument ever yet invented can equal the human voice in the music of its tones, in its range, in the different variety and quality of tones it can produce, and in its wonderful power of expression. The human voice is a combination of reed organ, pipe organ, trumpet, and violin; and can produce in its tiny music box--only about two inches long by one inch wide--all the tones and qualities of tones that can be produced on all these instruments, except that it cannot go quite so high or so low.

All the musical instruments in the world, from the penny whistle to the grand piano, are but poor imitations of the human music box. The bellows, of course, of the human pipe organ are the lungs; while the tongue furnishes the stops; and the throat, mouth, and nose, the resonance, or sounding, chambers.

Just as a violin, or guitar, has two main parts,--a string, which vibrates and makes the sound; and a box, or hollow body, which catches that sound and enlarges it and gives it sweetness and vibration and quality,--so the human voice has two similar parts--the vocal bands, which make the sound; and a sound box, or rather series of three resonance boxes,--the throat, the mouth, and the nasal pa.s.sages,--which enlarge and soften it and improve its quality.

You would naturally think that the strings, or cords, were the most important part both of the voice and of a musical instrument; and in one sense they are, as it could make no noise at all without them. But in another sense, far more important are the sounding boxes, or resonance chambers. The whole quality and value, for instance, of a Stradivarius[32] violin, which will make it readily bring ten thousand dollars in the open market, are due to the skill with which the body, or sound box, was made; the quality of the wood used; and, odd as it may seem, even the varnish used on it--the strings are the same as on any five-dollar fiddle. This is almost equally true of the human voice.

While its size, or volume, is determined by the voice box and vocal bands, and its power largely by the lungs and chest, its musical quality, its color, and its expression are given almost entirely by the throat, mouth (including the lips), and nose. The proper management of these parts is two-thirds of voice training, and all these are largely under our control.

How a Good Voice may be Developed. If the nasal pa.s.sages, for instance, are blocked by a bad cold or a catarrh or adenoids, then nearly half the body of your violin is blocked up and deadened; half your resonance chamber is destroyed, and the voice sounds flat and dead and nasal. If, on the other hand, your throat be swollen, or blocked, as by enlarged tonsils or chronic sore throat, then this part of the resonance chamber is m.u.f.fled and spoiled, and your voice will be either entirely gone or hoa.r.s.e; though perhaps by driving it very hard you may be able to make a clear tone.

If you have an attack of inflammation or cold further down, and the vocal bands swell, or the mucous membrane lining the voice box becomes inflamed and thickened, then the voice is lost entirely, just as the tone of a violin would be if a wet cloth were thrown across the strings.

But disturbances in the voice box, or larynx, cause only a very small percentage of husky, poor, or unmusical voices.

A far commoner cause, indeed probably the commonest single cause of a poor, squeaky, or drawling, unmusical voice is careless and improper management of the mouth and lips. In the first place, you can easily show that such marked differences in sound as those of the different vowels are all produced by the mouth and lips. If you will prepare to say the vowels--_a, e, i, o, u_--aloud, and begin with _a_, and then hold your mouth and lips firmly in the same position, you will find that all the other vowels also come out as _a_. If, on the other hand, you begin with your mouth and lips in the rounded and somewhat thrust-out position necessary to say _o_, and try to repeat the rest of the vowels, you will find that you cannot say them at all, but only different forms of _o_. When you have convinced yourself of this, repeat the vowels loudly and clearly without stopping to think about the position of the mouth, and notice how your lips, the tip and base of your tongue, and your soft palate and throat all change their positions for each successive vowel.

If you will try to sing the scale, beginning with a comfortable note about the middle of your voice range, and letting your mouth take the shape for that note unconsciously, you will find that, as you sing up the scale, you change the shape of your mouth, lips, and tongue at every note, thrusting the lips and mouth further forward as if to whistle, narrowing the opening and closing up the back of your throat for the high notes.

On the other hand, as you sing down, you tend to open the mouth and lips more widely, to drop the bottom of your mouth--that is, the base of your tongue--toward your throat, and your chin down toward your chest.

Again you will find, just as in the case of the different vowels, that you can sing any tone clearly and musically after putting the mouth in precisely the shape that best fits that tone; and learning how to do this is a most important part of vocal training.

What we call words are simply breath sounds and voice-box sounds chopped into convenient lengths by the movements of the tongue and lips and throat. So when we come to the question of clear and pleasant speaking, or, as we term it, _articulation_, the lips and tongue have almost everything to do with making the difference between a clear, musical, and refined enunciation, which is so easy to understand that it is a pleasure to listen to it, and a slurred, drawling, squeaky, nasal kind of speech, which is as hard to understand as it is unpleasant to listen to.

Few of us can ever hope to develop a really great singing voice; but anyone who will take the pains can acquire a clear, distinct, and pleasing speaking voice; and perhaps half of us can learn to sing fairly well. But to do this, we must first have good, healthy, well-developed lungs and elastic chest walls, which can come only from plenty of vigorous exercise in the open air, combined with good food and well-ventilated rooms. We must have a healthy stomach, which will not fill up with gas and keep our diaphragms from going down and enlarging our chests properly; we must have clear nasal pa.s.sages, good teeth, well-shaped mouths and flexible lips, which we are willing to use vigorously in articulating, or cutting up our voice sounds; and we must have good hearing and a well-trained ear. In short, the best way to get a clear, strong, pleasant voice is to have a vigorous, well-grown, healthy body.

FOOTNOTES:

[32] A famous violin-maker who lived about 200 years ago in Cremona, Italy. Fifty thousand dollars has been asked for an unusually choice "Strad."

CHAPTER XXV

THE TEETH, THE IVORY KEEPERS OF THE GATE

Why the Teeth are Important. The teeth are a very important part of our body and deserve far more attention and better care than they usually get. They are the first and most active part of our digestive system, cutting up and grinding foods that the stomach would be unable to melt without their help. In all animals except those that have horns or fists, the teeth are their most important weapons of attack and defense. So important are they in all animals, including ourselves, and so closely do they fit their different methods of food-getting and of attack and defense, that when scientists wish to decide what cla.s.s, or group, a particular animal belongs to, they look first and longest at its teeth.