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ferent, altogether, without let or hindrance, into the bowels ; for the sentry-box is deserted—the watchiman is dead. · When I contemplate this state of things, I think I see a whole army of diseases marching in file out of the stomach, through the pyloric gateway, into the citadel of the bowels. I see pale-faced and bloated Dropsy with his swollen legs,-livid Asthma struggling for breath-grotesque and tottering Palsy,-yellow-visaged Jaundice, red-eyed Delirium,—Fever, with his baked lips and parched tongue, looking piteously around and crying, “Water ! water!”limping Gout grinning with pain,-musing Melancholy, hideous Insanity,—but let us drop the curtain over a picture so horrible. My mind's eye aches with looking at it. Above all things, my dear John, take care of your pyloric valve.

Now let us get on a step further.

The food, having been thoroughly and properly acted on by the gastric juice in the stomach, is reduced to a uniform, bland fluid, called chyme, and this is the first great change in that succession of changes which is ultimately to convert it into blood. There is now neither bread nor meat in your stomach, there is nothing there but chyme, which is neither meat nor bread, but a fluid, the nature of which is one degree nearer to the nature of blood than it was before it became chyme. • The chyme, then, flows to the lower extremity of the stomach, presents itself at the pyloric valve, and having been examined, as it were, by the SENSIBILITY of that valve, and reported “ all right," is admitted into the duodenum.

The first twelve inches of the bowels, reckoning from their junction with the stomach downward, are called the duodenum.

Now the chyme in the duodenum has precisely the same effect upon the excretory ducts of the liver and pancreas, which open into the duodenum, as the food had in the mouth upon the excretory ducts of the salivary glands : that is to say, it stimulates the mouths of these excretory ducts, and this stimulation is propagated along the ducts to the glands themselves,—the liver and pancreas. These glands, so stimulated, pour out an increased quantity of their individual secretions, viz. bile and pancreatic juice. The surface of the bowel itself, too, (the duodenum,) pours out an increased quantity of fluid, called the intestinal juice. The chyme mingling with these juices, another remarkable change is effected :--the chyme is no longer chyme; it has lost its identity, and the result is a milky fluid, called chyle, destined to become blood, and an excrementitious matter ---the dross, if I may so speak - destined to be expelled from the body by the bowels.

This conversion of the chyme into chyle forms the second great change, by which that which was once food—bread and meat-has been advanced two degrees more nearly to the nature of blood.

I hope you have not yet forgotten that the chylous absorbents arise, by open mouths, from the internal surface of the bowels. As the chyle, therefore, flows along the duodenum, it comes into contact with these same open mouths of the chylous absorbents. These, by virtue of their sensibility, become aware of the presence of the chyle, which is stimulating them to action. They answer the call by erecting themselves, protruding themselves forward, dipping, as it were, their mouths into the chyle, and then retracting and closing them; they thus perform an actual suction, by which the chyle is drawn within the calibre of these beautiful little vessels. ..The chyle, thus absorbed, travels along the lacteals, (that is, the chylous absorbents,) is filtrated through their glands, is emptied into the thoracic duct, and by it is poured into the blood of the veins about the bottom of the neck, and is carried by the current of the blood through the right side of the heart, along the pulmonary artery, into the lungs.

While the chyle is traversing the chylous absorbents and their glands, it undergoes a change the nature of which is not understood ; but it is a change which advances it another degree nearer to the nature of blood. By the time, therefore, that your dinner, or, rather, that which was once the food which constituted your dinner, has reached your lungs it has become almost blood : but it has not yet become quite blood. .. When the chyle has reached the lungs, it is then exposed to the action of the air which we inhale, in the manner which I have described when speaking of the circulation of the blood. Here the final change is effected, and that which was bread and meat has entirely lost all its prior characteristics. It was first food, then chyme, then chyle. Now it is none of these. It has acquired, by virtue of the agency of the air in the lungs, the colour and all the other qua. lities and properties of blood. In a word, it has become blood itself. Thus, comparing the animal economy to the economy of vegetable life, one might say, that the stomach and bowels are the soil, the food is the seed which is sown in it, and blood is the fruit which that seed produces--a fruit which is destined to become the food of the animal. For, as was justly said by Hippocrates, “there is but one food, although there are several forms of food.” However various the viands may be which we put into the stomach they must all be converted into one and the same Auid, viz. blood, before they can have any effect whatever in nourishing or strengthening the body. Blood, then, is the sole nourishment on which we subsist; the food which we eat being no more than so much seed sown with the view of producing a nutritious fruit, by which the body is to be fed, and its health and strength sustained, viz. blood. We are no more nourished or fed by the food we eat than sheep are nourished by the turnip-seed which the farmer sows. The turnip-seed rots and loses its identity, but in doing so it gives rise to a turnip, and it is upon this turnip that the sheep feeds, and not upon the seed which was sown. And, in like manner, the food which we eat loses, like the seed, its nature and identity, but in doing so it produces blood, and it is by this blood that our bodies are fed, nourished, and sustained, and not by the bread and the meat that we put into the stomach. For as the turnip is not the seed, but the product of the seed, so neither is the blood food, but the product of the food, and it is from these new products that both the sheep and ourselves derive our strength. Hence becomes manifest the utter impossibility of deriving any manner of nourishment or strength from substances which are incapable of being converted into blood : for example, ardent spirit. No mechanism, no chemistry, no power, no magic is capable of converting brandy into blood.

Hitherto, then, we have only seen the seed sown and the proper fruit produced. We have now to mark the manner by which the body is fed and nourished by this fruit. By the way, I may as well take this opportunity of calling upon you to take notice how little the quantity which we eat has to do with the quantity of nourishment which we derive from it. For as the stomach, liver, &c. can only furnish, at one time, enough of their several juices to convert a certain portion of what we eat into chyme and chyle, it is manifest, that only a certain portion can be converted into blood. And as blood is the sole aliment from which we can derive nourishment, it is equally manifest that we can derive no nourishment from what we eat except from that portion of it which is converted into blood. All that we eat, therefore, beyond what can be converted into blood, is left in the stomach and bowels to ferment and putrefy, serving no other purpose than to distend these organs with all sorts of pernicious and offensive gases.

You will also see, now, how true it is that to talk about strong stomachs is, in fact, only to talk strong nonsense. For you have been reading for the last ten minutes to but little purpose if you have not remarked, while tracing the food from its existence as food to its existence as blood, that the stomach answered no other purpose than simply that of a bag, whose office it is to receive the food, to detain it for a given time, and then empty it into the bowels. The strength which is requisite to assimilate our food in the stomach, to convert it into healthy chyme, is not the strength of the stomach, but the strength of the arteries, whose office it is to bring to the stomach an abundant supply of blood, from which an abundant supply of gastric juice may be poured upon the food; and the strength of the heart, whose office it is to propel the blood into those arteries ; and the strength, if I may so speak, of the nerves, whose office it is to ascertain the presence of food in the stomach, to communicate the information to the heart and arteries, and thus to make these organs aware of the instant necessity which there is that they should exert themselves, in order that a ready supply of blood may be furnished, in order that a ready supply of gastric juice may be secreted, in order that the food may be readily and speedily reduced to chyme. The strength of the stomach has about as much concern with the chymification of our food as the strength of an iron pot has to do with the boiling potatoes. My dear John, never talk of the strength of your stomach, since it would argue marvellously little for the strength of your understanding; discard the phrase from your vocabulary; “I pray you, avoid it altogether.” False phrases give rise to false notions, and false notions to false applications. For instance, must not wrong notions of disease necessarily occasion the exhibition of wrong remedies ? They have done so; and hence it is that our excellent progenitors conceived the beautiful idea of strengthening the stomach; and forthwith that most unhappy organ (which is to the rest of our organs what the costermonger's ass is to the rest of the animal creation, the focus, as it were, towards which every species of abuse and cruelty is directed,) was smothered, and deluged, and drowned in all sorts of villainous infusions, and decoctions, and solutions, the bitterer and beastlier the better; and bark and wine, bark and milk, (precious compound !) camomile tea, the filings swept from the floor of a blacksmith's shop, and, in short, almost everything in the animal, vegetable, and mineral creation, provided always that it was very nau. seous, was, in its turn, esteemed “ the sovereignest thing on earth” for a weak stomach. But conceive my meaning rightly. I do not deny the utility of these drugs in certain diseases:- bark, for instance, cures the ague, but not by strengthening the stomach ; and my object, in these letters, is to give you a right notion of things, and not a wrong one, which I should certainly do if I were to allow you to suppose that the benefit occasionally derived from these remedies depended upon any power which they possess of strengthening the stomach. If we are weak, nothing but a copious supply of blood furnished to all our organs can strengthen us. I tell you, nature has appointed but that one source from which we can derive strength, and in order that that source might never fail us, in order that sufficient blood might always be derived from the food we eat, she placed us in a situation favourable to the conversion of our food into blood. She established a fixed relation between ourselves and the rest of the world; she taught us, by the very manner in which she fashioned us, what were the habits proper to our nature : she said, “ Here shall you stand, and thus shall you do, and while you are content to remain thus all shall be well ; disobey, and you shall surely suffer.” But we have quitted the position appointed us, we have forsaken the habits which she allotted us, we have disregarded her tokens, derided her counsel, broken her laws, overleaped her boundaries, and now that we are paying the penalty of our frolic, we stand gaping at each other like fools, and wonder what is the matter with us. The matter! why we are like Rabelais' wooden-pegs-we are square men, who have thrust ourselves into round holes :-no wonder we are uneasy-we don't fit. Is it possible that a square man can be jammed into a round hole without having his corners pinched- and his corns too? But of this I shall have more to say at a future time, when I hope to ring such a peal in your ears as shall make you heartily ashamed of the lazy and luxurious life you lead.

In order to exhibit the manner in which the body is nourished that is, the manner in which the fluid blood is converted into the solid parts of the body, it will, I think, be better to trace to this consummation only a single drop of blood at a time. You will, by this method, more readily understand it. But, by a drop, I do not mean a great, round, pumpkin of a thing, like a rain-drop or a dew-drop, but a delicate, minute globule, visible only to the eye of imagination, like the glowworm's tear of disappointed love when she lighteth her lamp in vain.

You have just seen the fresh chyle taken up by the chylous absorbents, and emptied by the thoracic duct into the veins at the bottom of the neck. Let us follow a single minute globule of this chyle.

Hurried along by the current of blood in these veins, it passes through the right side of the heart, along the pulmonary artery, then

along one of its branches, into the substance of the lungs. Here it is acted upon by the air in the cells of the lungs, loses its characteristics of chyle, and becomes blood. It now turns round, as it were, and hurries back again out of the lungs, along the pulmonary veins, to the left cavity of the heart.

But before we trace its progress any further, let us suppose that a hungry absorbent has just carried off a single particle from the point-the extreme protuberant tip of your organ of smell—" the very topmost, towering height o Johnny's nose.The carrying off this particle would necessarily leave a little hole. Now let us go back for our little globule of blood which we have just traced from the lungs to the left cavity of the heart.

Rejoicing in its new existence, it leaps out of the heart into the aorta, hence into the carotid artery, thence into the external carotid, thence into the facial, thence into the superior coronary, and thence into a minute branch which the superior coronary gives off, which branch takes its course toward the tip of your nose-a nose, my dear John, which, I must do it the justice to say, would suffer nothing in the comparison, though it were placed side by side with that of the unfortunate Diego, whose nose set all Strasburg in an uproar, and to obtain but a single peep at which, Slawkenburgius, apud Lawrence Sterne, declares, “ seven thousand coaches, fifteen thousand singlehorse chairs, and twenty thousand waggons, crowded as full as they could hold with senators, counsellors, syndicks, beguines, widows, wives, virgins, canons, concubines, the abbess of Quedlingberg, the prioress, the deaness, and subchantress, all set out at sun-rise." ...

By the time the artery, along which the little globule of blood is travelling, has nearly reached the tip of your nose, (worthy to be called proboscis,) it has become exceedingly minute and its course tortuous, for it is now forming part of the ultimate tissue of the tip of the nasal promontory. The little globule, therefore, now moves along with considerable rapidity. Gradually it approaches nearer and nearer, and just when it has arrived exactly opposite to the little hollow left by the absorbent, becoming suddenly obedient to the secret agency of the nerves, its nutritious elements dart through the coats of the artery, like rays of light through glass, into that hollow, and at that instant become part and parcel of one of the most goodly noses within the four seas. The artery now turns back, soon loses the characteristics of an artery, and becomes a vein, by which vein the rest of the little globule is conveyed back, through the heart, to the lungs, there to be mingled with fresh chyle and revivified by the action of the air in their cells.

This transformation of the fluid blood into the solid body is called solidification

Now this is the way in which all the solid parts of your body are formed and nourished; every inch of it, therefore, once floated in your arteries in the shape and quality of blood, and you see how foolish it is to suppose that there can be any real nutriment in those strong drinks to which the multitude attribute so many nourishing properties. What an inscrutably mysterious power, too, is manifested in this process ! How wonderful that so common and simple an affair

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