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 coa.r.s.e 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 pa.s.s 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 pa.s.s, 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 pa.s.ses 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 pa.s.s unperceived by the _pylorus,_ over whose decisions we have no control, remember. It bangs the door to, be a.s.sured, 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 pa.s.s 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 sc.r.a.ped 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 pa.s.sed 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 Ca.n.a.l.

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. G.o.d 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 a.s.similate 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 pa.s.ses, 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 ca.n.a.l_; 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 gla.s.s, 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 pa.s.sing 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 pa.s.s till it has acc.u.mulated 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 pa.s.s 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 ma.s.s 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 acc.u.mulates, 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 pa.s.sed 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 const.i.tute 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 gla.s.s 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 pa.s.sing, 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 pa.s.sing 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 G.o.d 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 cla.s.s 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 a.s.sists 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 part.i.tion_, 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 ma.s.s 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 acc.u.mulation of excessively minute atoms, which, when united, form a somewhat compact ma.s.s, 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 quant.i.ty 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!