of the blood. Solomon seems to have known something of it, by his speaking of "the golden bowl being broken" at death, and "the pitcher broken at the fountain, and the wheel broken at the cistern."

The heart is kept in constant motion, we know not how, nor can the wisest anatomist in the world tell us. We know that the lungs have something to do in the case; and when once set a-going, we can form some idea of what keeps it in motion. Its motion can easily be felt by placing your hand on your left side. Palpitation of the heart is occasioned by violent action of the body, by fear, fright, or disease.

"How is the wisdom of the Creator displayed," says a distinguished anatomist, "in this constant action and preservation of the heart! One would think, from the complexity of this machine, and the delicacy of many of its parts, that it would always be liable to derangement, and that it would soon work and wear itself out. Yet it will go on night and day for fifty, seventy, or eighty years together, at the rate of one hundred thousand strokes every twenty-four hours, having at each stroke a great resistance to overcome, and will continue this for this length of time without disorder, cessation, or weariness."

The brief account I have now given you will not convey anything like a complete notion of the form, action, or the use of the heart, with the circulation of the blood; but enough has been said to give you some idea of "the wonderful mechanism bestowed on our frame, for the continuance of life, by the hand of a Being who is all-wise, all-powerful, and all-good, and whose bountiful care is equally extended to the preservation and happiness of the humblest creature in existence, which has been, equally with ourselves, called into life at his command, and for a wise and good purpose."

III.—THE LUNGS, WINDPIPE, AND EPIGLOTTIS next claim our attention.

1. The LUNGS, or Lights, as they are commonly called in the lower animals, from their spongy, light, cellular structure, are the organs of respiration or breathing. There are two of these organs in the chest, one on the right side, and the other on the left. Each of these divisions is formed into lobes, or large lumps, three belonging to the right lung, and two only to the left; the heart in the latter occupying the place of the corre

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sponding lobe on the opposite side. cut R L and L L, mark the right and left lungs, with the heart и lying between them, but chiefly on the left side. The lungs draw in and expel the air, and by these actions respiration is continually carried on. The lungs may be compared to a bellows or wind-chest in an organ, and blow their blasts at the rate of twenty or twenty-five in a minute, in an adult person; and at a still greater rate in children: and they continue these blasts, whether standing or sitting, sleeping or waking, as long as we live. The lungs are furnished with innumerable minute cells, the whole of which appear not unlike a honey-comb, or piece of sponge. They are of a light, elastic, spongy texture, being little else, indeed, than an interwoven series of air-tubes, air-cells, and blood-vessels. When we breathe out, or expire, all the air which is actually in the lungs is not expelled, but only a portion of it. Of course, when we draw in, or inspire, we merely introduce air in quantity sufficient to supply the place of that which is discharged.

It is well known that the commonest Cough has to do with the lungs, and it may be thus explained; the lungs and lining membrane of the Bronchi secrete a certain degree of mucus, or phlegm. When cold or damp is applied to the skin, it sometimes occasions a mass of blood to be thrown inwards upon these surfaces or membranes of the lungs, which increases the secretion of the mucus to a high degree. "Were this secretion to accumulate, it would soon fill up the air-cells of the lungs, and cause suffocation; but to obviate this danger, the Creator has so constituted the lungs, that accumulated mucus or other foreign body coming in contact with them, excites the convulsive effort called coughing, by which a violent and rapid expiration takes place, with a force sufficient to hurry the mucus or other foreign body along with it; just as peas are discharged by boys with much force through short tubes by a sudden effort of blowing. Thus, a check given to perspiration, by diminishing the quantity of blood previously circulating in the surface, naturally leads very often to increased expectoration and cough, or, in other words, to common cold."*

Consumption is a disease seated in the lungs, often attended with hectic fever, cough, &c. In this disease tubercles, or small tumours, are found on the surface and substance of the lungs. These are discovered by percussion, or by the use of an

* Combe's "Principles of Physiology," p. 57.

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instrument called the Stethoscope—a small wooden tube like a funnel,-one end of which is applied to the chest of the patient, and the other to the ear of the practitioner, by which he is enabled to hear whether the lungs are in healthy action or otherwise.

The action of the lungs is essential to life; for to live and to breathe are synonymous terms. Let the lungs have full play. The dress should not be so tight as to press closely on any part of the chest. To females we would say, Avoid, by all means, tight lacing. You may suppose that this improves the figure, but it only distorts it, and it is at the sacrifice of health, and sometimes even of life itself.

Next to the preservation of life, the most important use of respiration is that of forming the voice or speech. This is accomplished in part by

2. The WINDPIPE, or TRACHEA. This is a tube which extends from the mouth and nostrils down to the lungs. It passes down in front of the neck, where it may be easily seen and felt. It is made of gristle, and contains sixteen or eighteen rings. At its lower part it divides into two branches, one called bronchus, going to join the right section of the lungs, the other the left. The common disease called the bronchitis is an inflammation of the bronchi, or tubes which convey air to the lungs. The other malady, called the Wen, or Bronchocele, and by the French Goître, is a tumour lying on the Trachea. It is sometimes called the "Derbyshire neck." It is very common among the females of Switzerland. The upper part of the windpipe is called the LARYNX, which modulates the voice in speaking or singing. The larynx in men is larger than in women; hence the difference of voice in the sexes. Here the air from the mouth and nostrils is admitted. On the top of it is

3. The EPIGLOTTIS. This is attached to the root of the tongue. It is a sort of little tongue reversed, and acts like a trap-door on the windpipe; for it fits to the opening as exactly as a trap-door was ever fitted to its frame. It is not often

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shut, however, except when we attempt to swallow. the substance, and the motion caused by this operation, press it down, and close it perfectly tight; and it is well that it is so; for if it were not, the food would often drop into the passage to which this trap-door opens, and create convulsive coughing, and probably disease and even death might ensue. How painful this is may be remembered from the irritation

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which is felt when a crumb of bread, or drop of liquid may, as is commonly and truly said, 'go the wrong way." young persons avoid holding pins, nails, buttons, and other such things in the mouth, as well as laughing and talking while eating; for it is at the least always dangerous, and may prove fatal.

There is another little tongue or flap, called the UVULA, attached to the roof of the soft palate, and seen above the arch of the tongue when the mouth is opened. It is peculiar to man, and the ape tribe: its use is to assist in speaking and swallowing. This, which guards the passage to the nose, is not, however, to be confounded with the other, which is further down the throat, and invisible.

The organs we have been just describing, viz., the Heart, Lungs, &c., are contained in the upper portion of the trunk of the human body, called the Thorax (from wpa, a coat of mail), or Chest. This is enclosed by the ribs, having the sternum or breast-bone in the front, and a portion of the bones of the back behind. It is separated from the liver, stomach, intestines, &c., by

IV. THE DIAPHRAGM.

This word is derived from the Greek Aa, through, and Peayua, an enclosure. It is vulgarly called the Midriff. It is a strong skinny muscle, or fleshy partition, spreading in an arch-like form under the heart and lungs, and over the liver, stomach, and bowels. (See fig. D D.) It is greatly concerned in the act of respiration, as it rises and sinks as we breathe. The acts of coughing, sneezing, speaking, laughing, gaping, and sighing, could not take place without its assistance.

The lower part of the body, under the diaphragm, is called the ABDOMEN.

V. THE STOMACH, AND GASTRIC JUICE must now be noticed.

1. The STOMACH. (See fig. Stm.) This is an oval bag of considerable size, occupying a slanting position immediately below the heart, with its right side overlapped by the left edge of the liver, and extending to the lower end of the breast bone. In figure, it nearly resembles the pouch of a bagpipe, varying in its capacity from five to eleven pints. It has two openings,

*House I Live in," p. 149.

both on its upper part;-the left, called the CARDIA, is that through which food and drink pass down from the mouth by the ESOPHAGUS, or gullet, or food-pipe ;-the right, called the PYLORUS, is that through which the aliment, when it is digested, is conveyed out of the stomach into the intestines, or bowels. The first bowel is called the DUODENUM, (so named in consequence of its length being twelve inches), in which the aliment undergoes other changes. The stomach is a remarkable vessel, or bag, the functions of which are not easily explained or understood. Dr. Hunter, in one of his Lectures to his medical students, said, "Some physiologists will have it that the stomach is a mill; others, that it is a fermenting-vat; others again, that it is a stew-pan; but in my view of the matter, it is neither a mill, nor a fermenting vat, nor a stew-pan;-but a stomach, gentlemen, a stomach."

This organ secretes a peculiar fluid named

2. The GASTRIC JUICE, so called from Taong, the stomach. This is clear and colourless, with little taste or smell; it is something like saliva or rennet. It seems to ooze out from the inside coats of the stomach like drops of sweat. It is a very powerful solvent, dissolving bone, and very hard substances: it has been known, after the death of a person, to eat into holes the stomach itself, if food has recently been eaten; for it is food that stimulates the juice, as salt in the mouth will stimulate saliva. "The contact of solid food with the inside of the stomach," says Dr. Carpenter, "is the proper excitement to the secretion of the gastric fluid. Soups and such like are not alone fit for the support of the system, even though they may contain a large amount of nutritious matter. The Greenlanders, it is said, mix earth or saw-dust with the train-oil, on which alone they are frequently reduced to live. One of them being asked the reason of the practice, replied, 'I cannot tell you, but I know the belly must be filled.' The gastric juice, when poured upon the food, is thoroughly mixed up with it by a peculiar action of the stomach, which is continually bringing into contact with its sides, fresh portions of the alimentary mass, so that the whole is, after a time, equally exposed to the influence of the fluid. If this movement were not to take place, only the outside of the mass would be digested, and the central portion would remain but little affected. It is a fact of great practical importance that a certain quantity of the gastric juice can act only upon a limited amount of food; so that if more food be swallowed than is required to repair the