If you were a grown-up lad, and I were teaching you natural philosophy, I should have here a fine opportunity for explaining what is called the theory of the lever. But I think the theory of the lever would frighten you; so we must get out of the difficulty in some other way.
I find, however, that I have been joking so much as I went along, that I have but little space left, and feel quite ashamed of myself. We seem quite unlucky over these teeth.
I have already been scolded by people who are not altogether wrong in accusing me of losing my time in chattering, first of one thing and then of another. They complain that by thus nibbling at every blade of grass on the way-side we shall never get to the end of our journey; and there is some truth in what they say. Still, I will whisper to you in excuse that I thought we might play truant a little bit while we were on familiar ground, where naturally you were sure to feel a particular interest in everything. The hand, the tongue, the teeth—these are all old friends of yours—and I thought you would like to hear all about them. By-and-bye we shall be in the little black hole, and then we shall get on much more rapidly.
LETTER VI.
THE TEETH (continued).
I left off at the molars, which are the teeth one selects to crack nuts with; and if I remember rightly, we talked about different ways of cutting with scissors.
Let us look at the subject from a distance, that we may understand it more clearly. Let us imagine a horse drawing a heavy cart slowly along. Ask it to gallop, and it will answer, "With all my heart! but you must give me a lighter carriage to draw." And now fancy another flying over the ground with a gig behind it. Ask it to exchange the gig for the cart, and it will say, "Yes; but then I shall have to go slowly."
Whereby you see that with the same amount of strength to work with, one has the choice of two things: either of conquering a great resistance slowly, or a slight one quickly.
And it is partly on this account, dear child, that I teach you so gradually; for young heads, fresh to the work, are less easily drawn along than others, and have but a certain amount of strength.
Hitherto all has been clear as the day. Now take your scissors in your left hand; hold the lower ring of the handle firmly between your thumb and closed hand, so that the blade shall remain straight and immovable: then with your other hand cause the upper ring to go up and down, and watch the blade as it moves. The whole of it moves at once, and is put in motion by the same power—viz., your right hand. But the point makes a long circuit in the air, while the hinge end makes only a very little one—indeed, moves almost imperceptibly: and, as you may imagine, a different sort of effort is required from the motive power (your hand) according as resistance is made at the point or at the hinge. The point goes full gallop: it is the horse in the gig; the light work is for him. The hinge moves slowly; it is the cart-horse, and takes the heavy labor.
I hope I have made you understand this, for it explains the cracking of our nut, though you may not suspect it. Move your scissors once more in the same way. Now, you have before you the pattern of the two jaws on one side of your face, from the ear to the nose; the upper one, which never moves (as you may convince yourself by placing a finger on your upper lip when you either speak or eat), and the lower one which goes up and down. Two pairs of scissors set points to points give you the whole jaw. The incisors are at the points, they gallop up and down, and are worthless for doing hard work; the molars are at the hinges, and move slowly; and if anything tough has to be dealt with, it comes to them as a matter of course; hence they are the nutcrackers. You must own that it is pleasant to reflect thus upon what we are doing every day, and the next time you see a stonemason moving stones of twenty times his own weight with his iron bar, ask your papa to explain to you the principle of the lever. After what I have told you, you will understand it very readily, or at least enough of it to satisfy your mind.
But, besides this power of moving up and down, the lower jaw possesses another less obvious one, by means of which it goes from right to left. This is precisely what naughty children make use of when they grind their teeth: not that I mean this remark for you, for I have a better opinion of you than to suppose you do such things. Those who make such bad use of their jaws deserve to lose the power of ever moving them thus, and then they would find themselves sadly at a loss how to chew their bread—for their molars would be of but little service to them in such a case; as it is chiefly by this second action of the jaw that the food is pounded. Try to chew a bit of bread by only moving your jaw up and down, and you will soon tire of the attempt.
One word more to complete my description of the teeth: that portion of them which is in the jaw is called the root; and the incisors, which cannot work hard because, like the gig-horses, they have but little resisting power, possess only small and short roots; whereas the canines, whose duty it is to tear the food sideways, would run the risk of being dragged out and left sticking in the substances they are at work upon, if they were not well secured; these, therefore, have roots which go much deeper into the jaw, and in consequence of this they give us more pain than the others when the dentist extracts them: those famous eye-teeth, which so terrify people on such occasions, are the canines of the upper jaw, and lie, in fact, just below the eye.
The molars meanwhile would be in danger of being shaken in the sideway movement, while chewing: so they do as you would do if you were pushed aside. Now you would throw out your feet right and left in order to steady yourself, and thus the molars, which have always two roots, throw them out right and left for the same purpose. Some have three, some four, and they require no less for the business they have to do.
Above the root comes what is called the crown; that is the part of the tooth which is exposed to the air; the part which does the work, and which bears the brunt of all the rubbing. Now, however hard it may be, it would soon end in being worn out by all this fun if it were not covered by a still harder substance, which is called enamel. The enamel which forms the coating of china plates, and which you can easily distinguish by examining a broken plate, will give you a very exact idea of it. It is this enamel which gives the teeth the polish and brilliancy we so much admire, and it is desirable to be very careful of it, not out of vanity, though there is no objection to a little vanity on the subject, but because the enamel is the protector of the teeth, and when that is destroyed, you may say good-bye to the teeth themselves. All acids eat into the enamel, as vinegar or lemon-juice does into marble; and one of the best means of preserving this protecting armor of the teeth is never to eat the unripe windfalls of fruit, which I have seen unreasonable children pick up in orchards and devour so recklessly. They give sufficient warning, by their acidity, that they are not fit for food, and when this warning is neglected, they take their revenge by corroding the enamel of the teeth; not to speak of the disturbance which they afterwards cause in the poor stomach.
I said that without this coating of enamel, the teeth would be prematurely worn out, the reason of which is, that the teeth have not the property of growing again, as the nails and hair have. When those little germs of which I spoke when we began to describe the teeth, have finished their work, they perish and fall out, like masons who, when they have built the house, take their departure forever.
But the "forever" wants explanation. For such stern conditions would fall hard on very little children, who, not having come to their reason, cannot be expected to understand the great value of their teeth, and take all the care they need of them. So to them a second chance is given.
Your first teeth, the milk-teeth, as they are called, count for nothing: they are a kind of specimen, just to serve while you are very young.
When you are approaching what is called the age of reason, (and this word implies a great deal, my dear child,) the real teeth, the teeth which are to serve you for life, begin to whisper among themselves, "Now, here is a little girl who is becoming reasonable, and who will soon, or else never, be fit to take charge of her teeth." No sooner said than done: other masons set to work in other cells, placed under the first set, and as the permanent teeth keep growing and growing, they gradually push out the milk-teeth, which were only keeping their places ready for them till they came.
This is just your case at present, and you now understand your responsibility, and how necessary it is to preserve those good teeth which have placed so generous a confidence in your care of them, and which, once gone, can never be replaced.
You have no loss by the exchange; you had twenty-four at first, you will now have twenty-eight. Twenty-eight, did I say? nay, you will have thirty-two; but the last four will come later still. The last molars on each side, above and below, in both jaws, will not make their appearance till you are grown up. They are a fastidious and timid set, and will not run any risks; and they are called wisdom-teeth, because they do not appear till we are supposed to have arrived at years of discretion. Some people do not cut them before they are thirty, and you will agree that, if they have not become wise by that time, they have but a very poor chance of ever being so!
There is much more still to be said about the teeth; but I think I have told you quite enough to teach you the importance of these little bony possessions of yours, which children do not always value as they deserve, and whose safety they endanger as carelessly as if they had fresh supplies of them ready in their pockets. If so many skilful contrivances have been devised for enabling us to masticate our food properly, it is clear that this process is not an unimportant one. Those, therefore, who swallow a mouthful after two or three turns, forget that they are thereby forcing the stomach to do the work the teeth have neglected to do, and this is very bad economy, I can assure you. You will see hereafter, when we speak about animals, that by a marvellous compensation of nature, the power of the stomach is always great in proportion to the _in_efficiency of the teeth, and that by the same rule, it is weakest when the jaws are best furnished. Now, no jaw is more completely furnished than the human one; it is clear, then, that it should do its own work and not leave it to be done by those who are less able: and the little girl who, in order to finish her dinner more quickly, shirks the use of her teeth, and sends food, half chewed, into her stomach, is like a man who, having two servants, the one strong and vigorous, the other feeble and delicate, allows the first to dawdle at his ease, and puts all the hard work on the other. He would be very unjust in so doing, would he not? And as injustice always meets with its reward, his work is sure to be badly done.
Now, the work in question consists in reducing what we eat into a sort of pulp or liquid paste, from which the blood extracts at last whatever it requires. But the teeth may bite and tear the materials as they please, they can make nothing of them but a powder, which would never turn into a pulp, if during their labors they were not assisted by an indispensable auxiliary. To make pap for infants what do we add to the bread after it is cut in little bits? Without being a very clever cook, you will know that it is water which is wanted. And thus, to assist us in making pap for the blood, Providence has furnished us with a number of small spongy organs within the mouth, which are always filled with water. These are called salivary glands. This water oozes out from them of itself, on the least movement of the jaw, which presses upon the sponges as it goes up and down. The name of this water, as I need scarcely tell you, is saliva.
When I call it water, it is not merely from its resemblance; saliva is really pure water with a little albumen added. Do not be afraid of that word—it is not so alarming as it appears to be. It means simply the substance you know as the white of egg. There is also a little soda in the water, which you know is one of the ingredients of which soap is made. And this explains why the saliva becomes frothy, when the cheeks and tongue set it in motion in the mouth while we are talking; just as the whites of egg, or soapy water, become frothy when whipped up or beaten in a basin.
But the albumen and the soda have not been added to the saliva, in our case, merely to make it frothy; that would have been of very little use. They give to the water a greater power to dissolve the food into paste, and thus to begin that series of transformations by which it gradually becomes the fine red blood which shows itself in little drops at the tip of your finger when you have been using your needle awkwardly.
When once minced up by the teeth and moistened by the saliva, the food is reduced to a state of pulp, and having nothing further to do in the mouth, is ready to pass forward. But getting out of the mouth on its journey downwards is not so simple an affair as getting into it by the front door, as it did at first. Swallowing is in fact a complicated action, and not to be explained in half a dozen words, and I think we have already chatted enough for to-day. I only wish I may not have tired you out with these interminable teeth! But you may expect something quite new when I begin again.
LETTER VII.
THE THROAT.
You remember a certain door-keeper, or porter, of whom we have already spoken a good deal, who resides in the mouth—the sense of taste, I mean?
Well, it is a porter's business to sweep out the entrance to a house, and you may always recognize him in the courtyard by his broom.
And accordingly our porter too has a broom specially placed at his service, namely, the tongue; and an unrivalled broom it is—for it is self-acting, never wears out, and makes no dust—qualities we cannot succeed in obtaining in any brooms of our own manufacture.
When the time has come for the pounded mouthful (described in the last chapter) to travel forward (the teeth having properly prepared it), the broom begins its work; scouring all along the gums, twisting and turning right and left, backwards and forwards, up and down; picking up the least grains of the pulp which have been manufactured in the mouth; and as the heap increases, it makes itself into a shovel—another accomplishment one would scarcely have expected it to possess. What it gathers together thus, rolls by degrees on its surface into a ball, which at last finds itself fixed between the palate and the tongue in such a manner that it cannot escape; at which moment the tongue presses its tip against the upper front teeth, forms of itself an inclined plane, and—but stop! we are getting on too fast.
At the back of the mouth, (which is the antechamber, as we said before,) is a sort of lobby, separated from the mouth by a little fleshy tongue_let_, suspended to the palate, exactly like those tapestry curtains which are sometimes hung between two rooms, under which one is enabled to pass, by just lifting them up.
If this lobby led only from the mouth to the stomach, the act of swallowing would be the simplest thing in the world; the tongue would be raised, the pounded ball would glide on, would pass under the curtain, and then good-bye to it. Unfortunately, however, the architect of the house seems to have economized his construction-apparatus here. The lobby serves two purposes; it is the passage from the mouth to the stomach, as well as from the nose to the lungs.
The air we breathe has its two separate doors there—one opening towards the nose, the other towards the lungs; through neither of which is any sort of food allowed to pass. But, as you may imagine, the food itself knows nothing of such spiteful restraints, and it is a matter of perfect indifference to it through which of the doors it passes. Not unlike a good many children who, though they are reasonable creatures, will push their way into places where they have been forbidden to go; and who can expect a pulpy food-ball to be more reasonable than a child? It was necessary, therefore, so to arrange matters that there should be no choice on the subject; that when the food-ball got into the lobby it should find no door open but its own, namely, that which led to the stomach. And that is exactly what is done.
You have not, perhaps, remarked that in the act of swallowing, something rises and contracts itself at the same moment in your throat, producing a kind of internal convulsion which jerks whatever is inside. People do not think about it when they are eating, because it is an involuntary action, and their attention is otherwise engaged.
But try to swallow when there is nothing in your mouth, and you will perceive what I mean at once.
Now, imagine our lobby at the back of the throat as a small closet, with a doorway in its wall, half-way up, the doorway being closed by a curtain. In the ceiling is a hole, which leads to the nose; in the floor two large tubes open out; the front one leading to the lungs, the one behind, to the stomach.
Now swallow, and I will tell you what happens. The curtain rises up and clings to the ceiling, and thus the passage to the nose is stopped up. The lung-tube rises along the wall, and hides itself under the door, contracting itself, and making itself quite small, as if it wished to leave plenty of room for the mouthful of food which is about to pass over it; and, for still greater security, at the very moment it rises, it pushes against a small trap-door which shuts up its mouth. No other road remains, therefore, but through the tube which leads to the stomach; the pulpy mouthful drops straight therein, without risk of mistake, and when it is once there, everything readjusts itself as before.
These are very ingenious contrivances, and I will venture to say that if we would but study the wonders of the marvellous and varied machinery which is constantly at work in our behalf within us, we should be much better employed than in learning things from which no practical good can be derived. Moreover, we should be ashamed to trust, like the lower animals, only to our instinct, (which, after all, is much less developed in us than in them,) for blindly escaping the thousand chances of destruction that beset a structure so fragile and delicate in its contrivances as the human body. Besides, it is not only our own machinery that is entrusted to us, we are liable to be responsible for that of others, whose development it is our duty to guard and watch; and how can we do this with a safe conscience, if we are ignorant of the construction, the action, the laws of all sorts which the great Artificer has, so to speak, made use of in forming our bodies?
When you, in your turn, are a mother, you dear little rogue, who sit there opening wide your bright eyes, and not comprehending a word of what I am saying, you will be glad that you were taught when you were little, how your own little girl ought to be managed. You will find a hundred opportunities of making good use, in her behalf, of what you and I are learning together, and in the meantime there is no reason why you should not yourself profit by the knowledge you have gained.
I am quite sure, for instance, that in repeating to your child the simple rule of politeness, with which everybody is acquainted, "Never talk when you are eating," you will be very careful to add, "and especially when you are swallowing," for reasons I am about to detail.
When we want to speak we have to drive the air from the lungs into the mouth, and our words are sounds produced by this air as it passes through. This is the reason why I advise you to go on gently, and make the proper stops in reading aloud: to take breath, in fact, as it is called; otherwise, breath would all at once fail you, and you would be obliged to stop short in the middle of a sentence and wait like a simpleton till you had refilled the lungs with air by breathing. It was for this purpose, also, and not for mere economy's sake, as you may have thought, that the little cross-road of four doors has been placed at the back of the mouth, enabling it to communicate at pleasure with either the lungs or the stomach. It is a dangerous passage for food-parcels making their way to the stomach; but if you could substitute for it, as it may have occurred to you to do lately, a simple tube going directly to the stomach,—behold! you would find yourself dumb;—a serious misfortune, eh? for a little girl! But come, I am quizzing too much, so console yourself. I know many grown-up people who would be at least as sorry as yourself.
To return to our subject. We have said that, in order to guard against accidents, the lung-tube is closed at the moment we are about to swallow. But if by any unlucky chance the air is coming up from the lungs at the same moment, it must have a free passage. Its tube cannot help returning to its place; the little trap-door which shuts up the opening opens whether or no, and then adieu to all the precautions of good Mother Nature! The mouthful when it drops, falls outside of its proper tube—that is to say, into the other, which is exactly in front of it, and we find that we have swallowed the wrong way.
You know what happens in such a case. You cough and cough till you are torn to pieces, till you grow scarlet, or even blue in the face; till you lose your breath; till your body trembles; till your eyes start out of their sockets. Let who will be there, there is no resource but to hide your face in your handkerchief. The tube, which was only made for the passage of air, on finding an intruder forcing an entrance, does its utmost to drive it back through the door. Then the lungs, which would be destroyed by its getting to them, come to the assistance of the faithful servant who is struggling for their protection: they agitate themselves violently, and send forth gusts of air which drive all before them. Thence arises the cough, and by this means at last the enemy is thrust out of the mouth, like dust before the wind. And it is only when the passages are cleared that the storm subsides. But the commotion is no laughing matter, I assure you; for if one had swallowed a little too far the wrong way, or if the substance swallowed had been too heavy for the air-tube, aided by the lungs, to eject within a certain time, death would have ensued: instances of which are by no means unknown. Nature does nothing in vain; this is no case of a man frightened by a mouse. When you find your whole being concentrating its efforts to one point, and betraying such distress, at an accident apparently so trifling, you may be sure there is danger, and real danger too; and if you doubt it, that makes no difference—happily for you.
Now you have learned why little girls should not attempt to talk and swallow at the same time, and, I may add, still less laugh; for laughingis a kind of somersault, performed by the lungs, and is always accompanied by the ejectment of a great deal more breath than is necessary in speaking, so that the jerks it occasions derange still more the wise provisions made to protect life whenever we swallow anything, and therefore we are more apt to swallow the wrong way while laughing than while speaking.
Need I say that we ought equally to guard against making others laugh or talk; or exciting, or frightening them, while they are swallowing; in short, avoid doing anything to create a sudden shock which might suddenly force the air out of their lungs, and cause them in the same manner to swallow the wrong way? Politeness requires this from us, and what I have now said will fix the lesson still more strongly on your mind. What would become of you if you were to see a person die in your presence in consequence of some foolish joke, however apparently innocent?
Not to conclude with so painful a picture, I will, before we part, give you the right names of the curtain, the lobby or closet, and the tubes of which we have been speaking.
The curtain is called the Soft Palate.
The lobby, the Pharynx.
The tube which leads to the stomach, the Aesophagus.
The tube leading to the lungs, the Larynx.
The opening of this tube is the Glottis, and the little trap-door which closes it when one swallows, is the Epiglottis.
You must excuse my attempting to explain the meanings of all these names; it would take me too long to do so. After all, the mere names are nothing. If I have succeeded in making you understand how all the different parts act, you may call them what you like.
Here we will rest. We are now on our way to where we shall see the large apartments, and be introduced to the master, that head of the house, whom no one can approach without so many ceremonies.
LETTER VIII.
THE STOMACH.
Once in the oesophagus (you remember this is the name of the tube which leads to the stomach), the mouthful of food has nothing to do but to proceed on its way. All along this tube there is a succession of small elastic rings, [Footnote: Properly, contractile circular fibres.] which contract behind the food to force it forward, and widen before it to give it free passage. They thus propel it forward, one after another, till it reaches the entrance to the stomach, into which the last ring pushes it, closing upon it at the same time.
Have you ever observed a worm or a leech in motion? You see a successive swelling up of the whole surface of its body, as the creature gradually pushes forward, just as if there was something in its inside rolling along from the tail to the head. Such is precisely the appearance which the oesophagus would present to you, as the food passes down it, if you had the opportunity of seeing it in action; and this has been called the vermicular movement, in consequence of its resemblance to the movement of a worm.
Here I wish to draw your attention to the very important fact, that this movement is in one respect of a quite different nature from that of your thumb when you take hold of a bit of bread, or that of your jaw when you bite with your teeth, or of your tongue, &c., when you swallow. All these actions belong to yourself, to a certain extent; they are voluntary, and under your own guidance; that is, you may perform them or not, as you choose. There is a constant connexion between you and them, and you knew what I meant at once as I named each of them in succession. But in speaking of this other movement we enter upon another world, of which you know nothing. Here is the black hole of which I spoke. The little rings of the oesophagus perform their work by themselves, and you have no power in the matter. Not only do they move independently of you, but were you to take it into your head to stop them, it would be about as wise a proceeding as if you were to talk to them. We will speak hereafter, in another place, of these impertinent servants, who do not recognise your authority, and with whom we shall have constantly to do, throughout what remains to be said on the subject of eating. The truth is, your body is like a little kingdom, of which you have to be the queen, but queen of the frontiers only. The arms, the legs, the lips, the eyelids, all the exterior parts, are your very humble servants; at your slightest bidding they move or keep still: your will is their law. But in the interior you are quite unknown. There, there is a little republic to itself, ruling itself independently of your orders, which it would laugh at, if you attempted to issue them.
This republic, to make use of another metaphor, is the kitchen of the body. It is there they make blood, as they know how; putting it to all sorts of uses for your advantage, it is true, but without your consent. You are in the position of the lady of a house whose servants have shut the door of the kitchen in her face that they may carry on their business after their own fashion, leaving only the housemaid and coachman at her command. It may be humiliating, perhaps, to be thus only partially mistress at home; but what can you do, my little demi-queen? I will tell you: make up your mind to govern the subjects under your orders as wisely as possible; and, as to the rest, be content with the only resource left you: viz., that of looking in at the window of the kitchen to see what goes on there!
The stomach is the head cook: the president of the internal republic. He has charge of the stoves; the whole weight of affairs is on his hands, and he provides for the interests of all. Aesop taught us this, long ago, in his fable of "The Belly and Members." [Footnote: La Fontaine's translation is quoted in the French original, where the name of the fable is "Messer Gaster," a more correct title than our own. Gaster is a Greek word signifying stomach; and it is strictly the stomach which is meant in the fable. From this comes, too, the medical term gastritis, the name of a disease of the stomach.—TR.] It is a very good fable, and was wisely appealed to once by a Roman Consul to appease a disturbance in the State. But the application was not quite fair in one respect; and since I have started the subject, I will satisfy myself by explaining to you where it was wrong. The time will not be wasted, for this fable has furnished information to a great many people about the economy of their insides, and possibly to you; and I should like you to know the exact truth of all the particulars alluded to. Whether Aesop understood them all, I cannot pretend to say; but the application by the old Roman to the quarrel between the big-wig senators and the people was on one point decidedly unjust; for there was, as far as facts are concerned, something to be said on behalf of the stomach, which Consul Menenius seems not to have thought of.
When you come to this part of the Roman history you will learn that the Roman Senate was a large and fat stomach, which did, it is true, furnish good nourishment to the other members of the State, but kept the best share for itself. We may say this now without risk of offence, it having been dead for so long a time. Our stomach is the leanest, slightest, frailest part of our body. It is master in the sense in which it is said in the Gospel, "Let him that is first among you be the servant of the others." It receives everything, but it gives everything back, and keeps nothing, or almost nothing, for itself. Between ourselves, Consul Menenius, the advocate of the Senate, had no business to talk to the poor wretches at Rome of any comparison between their government and so careful an administrator of the public good as a human stomach. He should have taken his subject of comparison from the families of geese or ducks—animals which have no teeth. These have strong, well-grown stomachs—true Roman senators—whose stoutness is in proportion to the work given them to do. But man provides his with work already prepared by chewing, supposing him to have had the sense to chew it, of course. It was not from a comparison with man, therefore, that Menenius ought to have got his boasted apologue, which was but a poor jest on the subject.
You did not expect, my dear, to come in for a lesson on Roman History in a discussion on the stomach. But the study of nature is connected with everything else, though without appearing to be so, and I was not sorry to give you, incidentally, this proof of the unexpected light which it throws, as we go along, upon a thousand questions which appear perfectly foreign to it. Look, for example, at this old fable cited by Menenius. For the two thousand years and upwards that it has been in circulation, troops of historians, poets, orators, and writers of all kinds, have passed it forward from one to the other, without having troubled themselves to investigate the laws of nature in connection with the stomach; therefore, not one, that I am aware of, has observed this small error, so trifling in appearance, so important in reality, which nevertheless is obvious to the first young naturalist who thinks the matter over.
But enough of the Romans. Let us return to our master—the head cook, if you choose to call him so.
I was telling you just now that he managed the stoves, and you may have thought that I was merely using similes, as I am apt to do. But not so: it is quite true that he cooks; and so now tell me, if you can, whence he gets his fire to cook with, or rather, to speak more correctly, who gives it to him?
Now you are quite puzzled, so I must help you out.
In the mansion we were talking about some time ago, to whom would anyone who wanted to light a fire, apply for wood?
I think you can answer this yourself, for you cannot have forgotten our famous steward, who gives everything to everybody. But, you will wonder, I dare say, how the blood can carry wood in his pockets. Wood? Ay, and real wood too, as we shall soon see: but it is not wood we are talking about now. The blood has something more to the purpose than wood in his pockets, for he has heat ready made. So when the stomach wishes to set to work, it appeals to the blood, which comes running from all parts of the body, and heats it so effectually that everything within is really and actually cooked. This is why one feels a sort of slight shudder down the back when the stomach has a great deal to do at once, for the blood being called for in a hurry, comes rushing along in great gushes, and carries with it the heat from the other parts of the body.
It is for this reason, too, that it is so dangerous to bathe when the stomach is at work cooking, because the cold of the water drives suddenly back all the blood which has accumulated around the little saucepan, and this causes such a shock in the body that people often die of it.
Do not ask me, to-day, where this heat of the blood comes from; we will speak of that hereafter. But I may tell you at once that our dear steward is not a bit cleverer in this matter than other people, and obtains his heat, like the humblest mortal, by burning his wood. Do not puzzle yourself to find out how. Enough that he burns it as we do, and by a similar process.
Well, in one way or another, the master cook has his fire at command. You know also, already, what it is he has to get cooked; namely, the pulpy stew, which has begun in the mouth by chewing, and which it is his business now to finish perfectly. Now see what a cook does who has got her stew over the fire. She turns and turns it again and again, and shakes the saucepan from time to time, that the ingredients may be more thoroughly mixed up together; and this is precisely what is done by the stomach; for all the time that the cooking is going on, he swells and contracts himself alternately, after the fashion of those rings of the oesophagus we were talking about, tossing and tumbling the food from one side to another, so as to knead it, as it were.
Again, the cook adds water to her stew from time to time to keep it moist; and so the stomach pours constantly upon his stew a liquid, which contains a great deal of water, and which flows in from a quantity of little holes, sunk in his delicate coats.
What more?
The cook puts in a little salt: and this the stomach takes care not to forget either, for he is a cook who understands his business. In the liquid of which I am speaking, there is, if not exactly salt as one sees it at table, at all events the most active part of salt, that which possesses in the highest degree the property of reducing everything we eat to a paste; and this is the real reason why we find all food so insipid which has not been seasoned with salt. As salt contains a principle essential to the work to be done by the stomach, some method had to be devised to induce us to provide him with it, and this method the porter up above has hit upon. He makes a face if we offer him anything without a little salt on it, as much as to say—"How can you expect them to cook you properly down below, my good friend, if you don't bring them proper materials?"
Upon which hint men have always acted from the beginning; and as far as we can trace history back, we find them mixing salt with their food, though without knowing the real reason why. It is the same, too, with the lower animals. They know nothing of the matter either, but this does not prevent their having a natural relish for salt, as any one will tell you who has the charge of cattle; for their stomachs require for their cooking the very same seasoning as our own, and therefore their porter above has received the same orders.
Salt is not the only thing, however, that exists in that liquid in the stomach. Learned men, after making minute researches, have found in it another equally powerful material, which is also found in milk. Therefore cheese, which contains this material as well as salt, is quite in its place at the end of dinner. It furnishes reinforcements for the stomach in cooking, and this is why you so often hear people say that a little cheese helps the digestion.
The digestion! Yes, that is the word I ought to have begun with. It is the real name of all this cooking; an operation after which I would defy you to recognise the nice little cakes you have eaten, any better than your mamma can trace her pretty rosy-cheeked apples in the jelly which she left on the fire two hours ago. The stomach, as you see, is very busy quite as long a time as that, and if we have to be very careful (as I pointed out before) not to disturb him too suddenly in his work after dinner, it is also important that we should not, while at dinner, give him more work to do than he is capable of doing. Although he is the master, he is but a puny fellow, as I have already pointed out; nevertheless, he works conscientiously, because he knows that the life of the whole body depends upon his exertions. Some people even say that in spite of his leanness he strips himself, at each digestion, of his interior skin, which he sacrifices to his work, and the fragments of which tend to increase and improve the stew which is entrusted to his care. Think of this, my dear, whenever a greedy fit comes over you, and recollect that such a disinterested public functionary deserves some consideration. Besides, there is serious danger, quite apart from any question of injustice, in overwhelming him with work. If your legs are wearied out, you have it in your power to lie in bed. If your arm is in pain, you can keep it at rest. But your stomach is like those poor people who have to support their families by the labor of each day. He, too, labors for others: he has no right to rest, no right to be ill, therefore; and when he begins to fail, woe betide you—you will have enough of it.
Children who have learnt nothing may laugh at all this, but you, my dear, are beginning to know something, and "science constrains," i.e. it has its claims and requirements. It requires you, to-day, not to be greedy, to-morrow, something else, and so on, continually, until you have become quite reasonable and wise. I am sorry for you if this vexes you, but it was your own wish to learn, and science constrains. Indeed, I will whisper to you in confidence that this is the best excuse people who are unwilling to learn have to offer for refusing. They do not know what learning may lead to, and what a pity it would be if they could no longer be greedy, or ill-natured, or selfish. What would become of us all in such a case?
LETTER IX.
THE STOMACH—(continued).
We made a very long story of the stomach last time, my dear child; and, after all, I see that there was one thing I forgot to tell you—viz., what it is like.
Have you ever seen a bagpiper, I wonder? A man who carries under his arm a kind of large dark brown bag, which he fills with air by blowing into it, and out of which he presently forces the same air into a musical pipe by pressing it gently with his elbow. If you never saw such a thing, it is a pity; first, because the bagpipe was the national instrument of our ancestors the Gauls, and is religiously preserved as such by the Scotch Highlanders and the peasants of Brittany—(two remnants of that illustrious race, whose history I recommend to your careful perusal some day); secondly, and it is this fact which has the greatest interest for us just now, because that large bag, which is the principal part of the instrument, gives you a very exact idea of your stomach; for in fact it really and truly is a stomach itself, and moreover, the stomach of an animal whose interior formation resembles yours very, very much.
And who do you suppose is this audacious animal, which presumes to have an inside so like that of a pretty little girl? Really, I am half ashamed to name him, for fear you should be angry with me for doing so. It is—it is the pig! The resemblance is not exactly a flattering one to you, perhaps, but we are all alike, and it would be worse than foolish to grumble at being created as we are. Moreover, there is one difference; the pig, who thinks of nothing but eating, has a very much larger stomach than we have, which is some consolation, at any rate.
Place the palm of your right hand on what is called the pit of the stomach, turning the ends of the fingers towards the heart; your hand will nearly cover the space usually occupied by the stomach, and you may figure it to yourself as a rounded and elongated bag, bigger above than below, making a very decided bend inside as it descends from the heart downward; something like one of those long French pears, called "Bon-chretiens," if it were bent in the middle, and the big end of it were placed next the heart. As for the exact size of the bag, there is no telling it, for it depends upon circumstances. It is a very convenient bag in that respect; just such a one as you would like to have in your frock for a pocket; only there would be a danger of your being tempted to put too many things into it. For as you fill it, it expands, and enlarges itself like an indian-rubber ball, which, though only the size of an egg to begin with, becomes as big as your head if you blow hard into it. Then, as it gets empty, it recovers itself, diminishing gradually in size in plait-like contractions.
When people remain too long without eating, they have, as they say, twinges in the stomach. This is because the stomach, becoming by degrees quite empty, and contracting more and more, the surrounding parts which were sustained by it, lose their support, and strain at their ligaments, which now have all the weight to bear. Careless people, who do not think of such things, are reminded by the twinging pains that it is time to eat, just as a careless servant is called to order by the bell of which his master has pulled the string.
In your case, my dear child, such warnings are soon attended to, and you have not always even to wait till they come. But there are hundreds of miserable beings who are warned to no purpose, who cannot obey the master when he calls for his rations, because they have nothing to give him; and when this forced disobedience lasts too long, they end by dying of it. In cases like these, when human beings thus cruelly perish, the stomach is found to be contracted till it is scarcely bigger than one's finger.
On the other hand, a man once died suffocated from excess of food, after one of those great public dinners, which last four, six, or more hours—one can scarcely say correctly how long—and the doctors who examined him found his stomach so prodigiously enlarged that it alone occupied more than one-half of his inside. As you perceive, therefore, the stomach has, properly speaking, no fixed size. Its size depends upon what there is in it. It is like those men whose manners go up and down with their fortunes; who seem very grand people when their pockets are well filled, but become very small ones when their purses are empty. There is, nevertheless, this difference between them, that such men are fools, because they are men, and not bags; whereas the stomach is a sensible bag, fulfilling with intelligence the duties of its character as a bag. It is very fortunate for us that it is ready to change its size, according to the caprices of our appetite; and dressmakers would do well if they could get a hint from it how to improve their style of pockets, which certainly cannot have cost their inventors any very great effort of imagination!
The way in which this extraordinary pocket empties itself is not less curious than the rest. As long as digestion is going on, the stomach is firmly closed at each end; at the upper one by the last ring of the aesophagus, and at the lower by another ring of the same kind, only stronger; the watchful guardian of the passage which leads to the intestines. This ring is called the pylorus.
For once, here is a name which agrees with our method of describing the human machine, and I have much pleasure in translating it to you, although it is a Greek word. Pylorus is the Greek for a porter; and our ring is indeed a porter like the one of which we have already said so much, and which I called last time the porter up above, in anticipation of his colleague below.
The porter up above presides at the entrance; the one below at the exit, and both for the same purpose, namely, to taste. [Footnote: It would be absurd to say so in the common acceptation of the term; but according to No. 1 of Mr. Mayo's "Classification of the impressions produced by substances taken into the fauces," viz., "Where sensations of touch alone are produced, as by rock-crystal, sapphire, or ice," the word taste may be applied to the discriminating faculty of the Pylorus.—TR.]
It may well astonish you, that you should have in your inside a taster who is not accountable to you; who experiences sensations of which you know nothing, and cannot even form an idea. Yet thus it is. The pylorus actually tastes the paste which is in the stomach, and if it is not to his taste, that is to say, if the work of digestion has not sufficiently transformed it for use, he keeps the door relentlessly closed.
The porter up above has a thousand different tastes. He makes his bow to meringues, and admits wings of chickens. Fries, roasts, stews, things tender or crisp, sweet and salt, oily, greasy, or sour; amongall kinds he has friends whom he welcomes in succession; and it is well for us that he does so, for we share in all his pleasures.
The porter below, who works for himself alone, obscure and unknown down in his black hole, the porter below, I say, has but one taste, knows but one friend—a gray-looking paste, semi-liquid, with a very peculiar unsavoury smell, disagreeable enough to any one but himself, which is called the chyme, I scarcely know why, but it is what everything one eats turns into, without exception, be it delicate or coarse by nature. The great lord's truffle-stuffed pullet makes, as nearly as possible, the same chyme as the charcoal-burner's black bread; and though the palate of the former may be better treated than that of the latter, the pylori can enjoy but one and the selfsame sauce. Equality is soon restored in this case, therefore, as you see.
To be free to pass through then, the contents of the stomach must be reduced to the condition of chyme, the only substance which finds favor with the pylorus: and as, in the endless varieties of food which go to form our nutriment, some sorts turn into chyme much more quickly than others, it follows, that by the aid of its discriminating tact (which is not easy to elude) the pylorus allows some to pass, while it turns back others, until all in succession are converted into chyme. For example, in the case of a mouthful of bread and meat swallowed at once, the bread passes away on its travels long before the meat has done dancing attendance in the stomach, awaiting that transformation without which the pylorus will never allow it to slip through.
This ought to make you seriously reflect on the danger of carelessly swallowing things, which, by their nature, are not susceptible of being converted into chyme, particularly if they are too large to hide in the general paste, as a cherry-stone will sometimes do, so mixed up with other food as to pass unperceived by the pylorus, over whose decisions we have no control, remember. It bangs the door to, be assured, in the very face of anything obnoxious without hesitation, and the poor stomach would find itself condemned to retain them for an indefinite period, unless by dint of prayers and supplications they should contrive to soften the stern guardian, who may at last get accustomed to their approach, and, perhaps, in a weak moment, allow them to pass as contraband goods; like a custom-house officer on a foreign frontier who will occasionally shut his eyes to a country friend's packet of tobacco. But the poor stomach has had to suffer a martyrdom meantime, while the dispute was pending, and before the intruder has been winked at by the porter.
I shall remember all my life the history of a peach-stone, which was related to me in 1831. I was at the time a youngster at the Stanislaus College, and (aided perhaps by the Revolution of July, which had recently occurred), it was just then discovered to be a proper thing to set about teaching the laws of nature to children. Consequently, for the first time in the history of schools, a professor of natural history was added to the instructors of Latin and Greek. I leave you to judge how we opened our ears to his lessons. When we arrived in the course of our new studies at the pylorus, of which we had none of us ever heard before, our professor, in warning us, as I have done you, of the dangers of imprudent gluttony, related, as an instance, the case of a lady who had inadvertently swallowed a peach-stone. For two years she suffered agonies in her stomach without any cessation or relief. The luckless peach-stone, repelled by the walls of the stomach, which its very touch irritated, was incessantly thrown against the entrance of the pylorus, but in vain. As to turning itself into chyme, such a thing was not to be thought of, it was far too hard a substance for that. Round and round it went, causing in its relentless course such renewed suffering to the poor patient, that she was visibly sinking from day to day.
The doctors, finding all their treatment of no avail, began to despair of her life, when one fine day she was suddenly, and as if by enchantment, relieved of her tormentor. The peach-stone had bribed the porter, with whom, in the course of the two years, it had scraped up a sort of friendship. It had cleared the terrible barrier, had been allowed to slip out, and the lady was saved; but it was only just in time.
I do not know, my dear, that this story, which is certainly well calculated to cure you of any fancy for swallowing peach-stones, willmake as much impression on you as it did on me five-and-twenty years ago. The idea of telling it to you occurred to me quite by chance. It has carried me back to the time when, as is now the case with you, the mysteries which lie hidden in our internal organization were beginning to be revealed to my mind; and you will one day know with what delight one recalls the remembrance of these first dawnings of the intellectual life—that delightful infancy of the growing mind—more rich in recollections, and more interesting a thousand fold than the infancy of the body. I have allowed myself the little treat of this episode, and if I have had the good fortune to amuse you at all during our progress, you must not cavil at this piece of self-indulgence. And now we have done just what the peach-stone did; we, too, have passed the barrier, and are out of the stomach, but still we have not yet come to the end of our tale.
LETTER X.
THE INTESTINAL CANAL.
I venture to hope, my dear child, that more and more light is dawning upon your mind, as we gradually proceed on our little journey. You must by this time have some idea how the food, which has been masticated and softened in the mouth, cooked, kneaded, and decomposed in the stomach, and transformed into a soft, semi-transparent kind of paste, will soon be ready to mix with the blood, in order to repair the waste that the life-stream is continually undergoing in its ceaseless course through all parts of the body.
You have perhaps thought it a sad degradation for a truffle-stuffed fowl to turn to chyme. But when you consider that by this means it becomes part and parcel of a human body, the change is not to be despised. It was necessary, to begin with, that materials destined to the honor of being incorporated into our frame, should break the links which bound them to the condition of fowl and vegetable, and thus be free to engage in new relations; just as a man who wishes to be naturalized in a new country must first break the ties which hold him to the old one. Those articles of food we were speaking of lately, which are so stiff and ceremonious, and want so much coaxing before they change into chyme, which, moreover, we call indigestible because they tire the stomach so much more than the rest, are merely those whose component parts being held together by more solid ties than usual, continue obstinately in the same state as at first, and will not consent to that dissolution which is the first condition of their glorious transformation.
Moreover, the transformation which has been described to you now, you will henceforth meet with everywhere; wherever, that is to say, and as far as, you choose to pursue the study of nature. God works by one grand and simple rule so far as we can discover. He destroys to reconstruct, builds up what is to be, out of the ruins of what has been, creates life by death, if I may so express myself, and thus, what takes place in our stomachs on a small scale goes on on a large one in the universe.
Social communities, like everything else, are subject to this universal law, and it is not always an advantage to them when they refuse to be digested in the great stomach of the age!
While we are on this subject, and to show you how wonderfully this little history of eating, told in this familiar style, applies right and left, let us reflect on the causes which have produced a great and mighty nation in one country (as in France), while in another (as in. Germany), a far more numerous and even more intellectual population has failed to rise to anything like the same distinction. The explanation is not difficult. In the one case, the petty tribes among which the land was originally divided consented to mix, and dissolve, and be digested as it were together, in order to revive again for a more glorious career; while in the other, the aboriginal societies have adhered stiffly to their distinctive characters, and failing to submit to the regenerating process, cling together in indigested portions, rather than assimilate into one great whole.
However, we must return to the pylorus or we shall be getting into a difficulty! What I am now going to offer you though, is rather hard of digestion, but it will not do to provide sweet pastry only for your brain; it will be more wholesome for it to have something a little more solid to bite at from time to time.
The pylorus, then, as has been shown, makes way for all sorts of aliments when they have been converted into chyme; i.e., when they have lost their original form and individuality. They are dead to their first life, therefore; now the question is, how are they to be revived into the new one?
Behind the pylorus extends a long conduit or tube—so long as to be sometimes seven times the length of the whole body, but doubled up backwards and forwards a number of times, so as to form a large bundle, which fills the whole cavity of the belly—or as we also call it, the abdomen. This bundle or packet is known to everybody as the intestines, and it is divided into two portions: the small intestine—that is, the slenderer, finer portion which begins at the pylorus, and forms all the doublings of the packet, and the large intestine, which is shorter and thicker also, as its name implies, and keeps to some extent separate, though it is in reality only a continuation of the other. This starts at the base of the abdomen, near the right side, goes up in a straight line to the height of the stomach, below which it passes, making a large bend in front of the small intestine; after which it descends on the left side to the lower part of the trunk, where it terminates.
You will perhaps inquire how the chyme continues to make its way through all these manifold twists of the intestines; but do not trouble yourself; it has only to let itself go. That vermicular movement which we noticed in the oesophagus and in the stomach is found here also. It reigns, so to speak, from one end of our internal eating-machine to the other; which eating-machine, by the way, we will now call by its proper scientific name—the intestinal canal; and it is by that movement the food is carried forward from the first moment it leaves the mouth, and helped through all its journeyings, till it reaches the termination of the large intestine.
If your body were made of glass, so that you could look through it to watch the intestine at work, it would appear to you like an enormous worm coiled up into a bundle, heaving and moving with all its rings at once. You never suspected there was such a movement within you; yet it has been going on there continually ever since you were born, and will not cease till you die. Your internal machinery never goes to sleep, not even when you are sleeping yourself. It is a workshop in constant operation, providing night and day for your necessities; and in this respect the inner man sets a first-rate example to the outer one! You will recollect what I said to you the other day about the internal republic, and the provinces which are under your sole government. It would be very disgraceful for the kingdom to be doing nothing while the republic is working so hard; and a queen who understands her office will make it a point of honor to banish idleness from her household; in the houses of her neighbors this word is unknown.
The chyme once launched into this moving tube, is in no danger of remaining stationary there; the fear is, of its passing on too quickly, as you will soon see. But this danger has been provided against. Along the whole course of its journey, though chiefly at the commencement, it encounters at intervals certain elastic fleshy valves which interrupt its progress, and do not allow it to pass till it has accumulated in sufficient force to push them before it, and so escape. In consequence of which it is always being checked in its advance; and during these stoppages a most important work goes on upon it at leisure.
You must understand first, that the substances of which our food is composed, and which are afterwards decomposed in the stomach, are not all invited to enter the blood. Our aliments are something like the stones which the gold-seekers of California reduce to powder in order to extract therefrom the hidden particles of gold they contain. The gold of our food is that portion of it which the blood is able to appropriate to his own advantage; the rest he rejects as refuse. And this explains why a small slice of meat nourishes you more than a whole plateful of salad. Meat is a stone absolutely full of gold, while the salad has only a few veins of it here and there, and by far the greater part of the material it sends to the intestines, has, in consequence, to be thrown away.
Now it is in the first portion of the small intestine, the part known by the Latin name duodenum, which signifies twelve (because it is about the length of twelve finger-breadths), that the division takes place between the parts which go to nourish the blood, and those which are useless refuse. It is an important operation as you may suppose, and were the chyme to pass rapidly through the small intestine the gold would run the risk of being carried off with the refuse.
After the delay in the stomach, the food-substances make another halt in the duodenum, which, being very thin and slender, would have great difficulty in containing them at the time of their grand entry, an hour or two after a meal, were it not that it possesses the property of expanding itself to such an extent, that it swells out on grand occasions to the usual size of the stomach itself, so that it has sometimes been considered as a second stomach. And no doubt the operation which takes place in it gives it a claim to the appellation, for thereby the finishing stroke is put to the work previously begun in the stomach, and one may fairly say that, but for this last touch, very little would be accomplished at all.
Above the duodenum, and hid behind the stomach, is a kind of sponge, similar in nature to those we have already observed in the mouth. To this has been given the somewhat ridiculous name of pancreas; I call it ridiculous because it is derived from two Greek words which signify all flesh; whereas the pancreas, which is a sponge of the same description as the salivary glands, presents the appearance of a grayish granulous mass which is not fleshy at all. Whatever be its name, however, our sponge communicates with the duodenum through a small tube, by means of which it pours into the chyme, as it accumulates, a copious supply of a fluid exactly like the saliva of the mouth.
Just by the place where the tube from the pancreas empties itself into the duodenum, another tube arrives bringing also a fluid, but of a different sort. This last comes from the liver, where there is a manufactory of bile—an unpleasant yellowish-green liquid, the name of which you have no doubt heard before, and which plays a very important part in the transformation of the aliments.
These new agents, the bile and the liver, are far too important to be passed over in a few words; I reserve them, therefore, for my next letter. Meantime, not to leave you longer in suspense, I may say that the separation between the gold and the refuse in the chyme takes place as soon as the latter has received the two liquids furnished by the liver and the pancreas. If you ask in what manner the division is accomplished, I confess, to my shame, that I am not able to explain it! What takes place there is a chemical process, and hereafter I shall have occasion to explain the meaning of that phrase. But the Great Chemist has not in this instance seen fit to divulge to man the secret of the work.
Indeed, you must prepare yourself beforehand, my dear child, to meet with many other mysteries besides this, if we pursue to the end our study of this flesh and bone which constitute the body of man. And here I recall what Camille Desmoulins is reported to have said about St. Just, viz., that he carried his head as high as if it were a consecrated Host.
[Footnote: The young Protestant reader who has never lived in a Catholic country, will perhaps need to be told, that what is here called Consecrated Host, is the sacramental wafer, or communion bread of the church. In French called hostie, in Italian, ostia.
In all their religious processions, which are very frequent, the host is carried by the priest highest in authority, in a glass box placed on a staff about four feet long, which he holds before him and so far elevated that he has to look up to it. Over his head a richly embroidered canopy of satin is always carried by several men; and while these are passing, all good Catholics uncover the head and bend the knee, wherever they may be.
It is the custom also for the priest to be called to administer the sacrament to any one about to die, on which occasion he always walks under this canopy, dressed in his priestly robes, carrying the host and preceded by some boys, ringing a bell, when the same ceremony is observed. In passing a regiment or company of soldiers, the column is halted, wheeled into line, and with arms presented, the whole line, officers and men, kneel before it, and the priest usually turns and offers a benediction. When he goes in the evening to the house of the dying, it is customary for the people to go out upon the balconies with lighted lamps and kneel while the host is being carried by.]
You will read about these two men by-and-by in history. Meantime I will not bid you do exactly the same as St. Just, because you would be laughed at; but in one point of view he was not altogether wrong. The human body is, in very truth, a temple in which the Deity maybe said to reside, not inactively, not veiling his presence, but living and moving unceasingly, watching on our behalf over the mysterious accomplishment of the everlasting laws which equally guide the chyme in its workings through our frames, and direct the sun in its course through the heavens. We mortals eat, but it is God who brings nourishment out of our food.
LETTER XI.
THE LIVER.
I fear you will be getting a little weary, my dear, of dwelling so long on this intestinal tube, where things which looked so well on one's plate become so transformed that they cannot be recognized, and where there is nothing to talk about but chyme, and bile, and the pancreas, and all sorts of things neither pleasant to the eye nor agreeable to the ear.
But what is to be done? It is always the same story with useful things. The people by whose labor you live in this world, are by no means the handsomest to look at, and so it is in the little world we carry about in our bodies.
Never mind! Keep up your heart. We are getting to the end. We shall very soon be following the nourishing portion of our food, on its journey to the blood, and you will find yourself in new scenes.
First, though, let us say a few words about the liver—the bile-manufacturer; and to begin with, I will describe the place he occupies in our interior.
The interior of the human body is divided into two large compartments, placed one above the other; the chest and the abdomen. These are two distinct apartments, each containing its own particular class of tenants: the upper one being occupied by the heart and the lungs (the respective offices of which I will presently explain to you); while in the lower are the stomach, the intestines, and all the other machinery which assists in the process of digestion. These two stories of apartments are separated as those of our houses are, by a floor placed just above the pit of the stomach. This floor is a large thin, flat muscle, stretched like canvas, right across the body; and it is called the diaphragm—another hard word! Never mind; but do your best to recollect it, for we shall have great need of it when we come to the lungs. If you had been born in Greece, you would have no difficulty with the word, for it is Greek for separation. It means, in fact, a separating partition, or, as I called it just now, a floor. All this is preparatory to telling you that the liver is hooked to the diaphragm in the abdomen. It is a very large mass and fills up, by itself alone, all the right side of the lower compartment, from the top downwards, to where the bones end which protect the abdomen on each side, and which are called the short ribs. Place your hand there, and you will find them without difficulty.
Large as the liver is, it hangs suspended to a mere point of the diaphragm, and shakes about with even the slightest movement of the body. It is partly on this account that many people do not like to sleep lying on the left side, especially after a good dinner, because in this position the liver weighs upon and oppresses the stomach, like a stout gentleman asleep in a coach who falls upon and crushes his companion at every jolt of the vehicle. The liver within you produces, then, the same effect that a cat, lying on the pit of your stomach would do, and the result is that you have the nightmare.
The liver is of a deep-red color. It is an accumulation of excessively minute atoms, which, when united, form a somewhat compact mass, and within each of which there is a little cell, invisible to the naked eye, where an operation of the highest importance to our existence is mysteriously carried on. It appears a very simple one, it is true, yet hitherto it has baffled all attempts at explanation. Listen, however; the subject is well worthy your careful attention, whether it can be explained or not, and we must look back to take it up from thebeginning.
I told you about the thousand workmen constantly busied in every part of our bodies, who call on the blood without ceasing for "more, more." You will remember further that it is to enable the blood to supply these constant demands, that we require food.
This being understood, it is not difficult to see why we grow; the difficulty is, rather, to explain why we do not continue to grow.
Consider, for instance, the quantity of food you have eaten during the last year. Picture to yourself all the bread, meat, vegetables, fruits, cakes, &c., piled upon a table. Put a whole year's milk into a large earthenware pan, all the sweetmeats into a large jar, all the soup into a great tureen, and see what a huge heap you will have collected together. Then try to recollect how much you have increased in size with all this nourishment, which has entered your body. But reckoning in this way—even supposing the little workmen had used only a half or even a third of the materials in question, and rejected the rest as refuse—you would have to stoop in order to get in at the door; and as for your papa, whose heap must have been bigger than yours, his case would be desperate indeed; and yet he has not grown at all!
This is very curious, and I dare say you have never thought about it before.
Do you know the story of a certain lady called Penelope, who was the wife of Ulysses, a very celebrated king of whom the world has talked for the last 3000 years—thanks to a poet called Homer, who did him the honor of making him his hero! The husband of Penelope had left her for a long time to go to the wars, and as he did not return, people tried to persuade her to marry again. For peace and quiet's sake, she promised to do so when she should have finished a piece of cloth she was weaving, at which she worked all day long. They thought to get hold of her very soon, but her importunate lovers were disappointed; for the faithful wife, determined to await the return of her husband, unwove every night the portion she had woven during the day; and I leave you to judge what progress the web made in the course of a year!
Now, every part of our bodies is a kind of Penelope's web, with this difference—that here the web unravels at one end as fast as the work progresses at the other. As the little masons put new bricks to the house on one side, the old ones crumble away on another—in this manner the work might go on forever without the house becoming bigger; while, on the other hand, the house is always being rebuilt. People who are fond of building, as some are, would quite enjoy having such a mansion as this on hand!
At your early age, my love, fewer bricks drop out than are added, and this is why you grow from year to year. At your papa's age, just the same number perish and are replaced; and therefore he continues the same size, although in the course of the year he swallows three times his own weight of food. But when I say this, do not suppose it is an offensive remark, or that I think him either too little a man, or too great an eater; seeing that there are 365 days in the year, and that a quart of water weighs two pounds: I need not say more!
But the next question is, what becomes of all the refuse which this perpetual destruction produces?
What becomes of it? Have you forgotten our steward who looks after everything? He is a more active fellow than I have represented him! To the office of purveyor-general he adds that of universal scavenger. But in the latter department he obtains help. Wherever he passes along, troops of little scavengers press forward, like himself always busy; and while he holds out a new brick to the mason as he hurries by, the little scavenger slips out the old one and conveys it away. The history of these scavengers is a very curious one, and we shall have to speak about it a little further on. They are minute pipes, i.e. ducts, spread all over the body, which they envelope as if with fine net work. They all communicate together, and end by emptying the whole of their contents into one large canal, which, in its turn, empties itself into the great stream of the blood. Imagine all the drains of a great town flowing into one large one, which should empty itself into the river on which the town was built, and you will have a fair idea of the whole transaction. What the river would in such a case be to the town, the blood is to the body—the universal scavenger, as I said before. But you will ask further, What does the blood do with all this?—a question which brings us back once more to the liver.