3. We have seen that the arterial blood-vessels carry nourishment from the heart to all parts of the system, and that, after the blood has performed this part of its duty, it gathers up, in the minute capillaries, the waste and worn-out particles of the body, for the purpose of throwing them away. Most of the refuse particles, which consist of carbon, uniting in the capillaries with the oxygen which the blood received on its passage through the lungs, and forming, by this union, carbonic acid gas, are carried to the lungs, and there separated from the blood, and breathed out into the air through the mouth and nostrils, in the form of carbonic acid gas and vapor. 4. But the perspiration-tubes also are all the time busy in performing the same kind of labor as the lungs, in purifying the blood. As these tubes, opening into the air, are lined with the capillary blood-vessels, the air which they contain is brought in close contact with the blood, just as the air is brought in close contact with the blood in the lungs; and waste and worn-out particles of the body, in the form of water, soda, potash, iron, oil, salts, and acids, and carbonic acid gas, are poured out into the perspiration-tubes, and by them carried to the surface of the body, and thrown out through the pores of the skin. 5. These numerous tubes are therefore constantly performing the process which we call perspiration. When we sweat freely they are very active, and perform a vast amount of labor. Each one of these tubes is about a quarter of an inch in length, including its coils; seventy-three feet of this tubing in one square inch of the skin, or twenty-eight miles of it spread over the body of a common sized man! 6. A wonderful apparatus,1 indeed! but not more wonderful than the amount and importance of the labor which it performs; for it is calculated that these little tubes carry off daily, through the skin of a full-grown active man, not less than two or three pounds of waste matter! These little workers are all the time engaged in this labor; and the blood from the arteries is just as busy in supplying the vacant places with new material! Thus physiologists tell me that my body —this house which I live in-is constantly being pulled down and undergoing repairs, and that there is not a particle of it which is the same now that it was ten years ago! 7. Thus we are dying every hour, nay, every instant; and the only difference between this death and that which occurs at the end of life (so far as regards the body) is, that in this gradual death the place of every dead particle is instantly supplied by a living one, while in the other case all the parts of the body perish together, and are not reproduced. In youth the building up process goes on more actively than the pulling down process; in middle life the two powers are equal; but in old age the pulling down process gains the ascendency, and the house we live in gradually falls to decay. 8. How strange it seems that ten years ago you had one body, and that now you have another! You can, indeed, see, hear, and taste as you could before; but the eye with which you see is not the same as the one you had ten years ago: it is a new eye; and you hear with a different ear, and taste with another tongue. Indeed, the eye of to-day is not the same as that of yesterday; for a part of the eye of yesterday has passed away, while the deficiency thus produced has been supplied by a part of yesterday's dinner! But the mindthe thinking power or principle of yesterday and of ten years ago that is within you still. Through all the changes and the many deaths of the body, the mind-the soul-still lives. "The purple stream that through my vessels glides, Dull and unconscious flows like common tides: The pipes through which the circling juices stray, Are not that thinking I, no more than they: This frame compacted,3 with transcendent skill, Of moving joints obedient to my will, Nursed from the glebe,5 like yonder tree Waxes and wastes; I call it mine', not me': New matter still the mouldering' mass sustains, The mansion changed, the tenant still remains; And from the fleeting stream, repaired by food, Distinct as is the swimmer from the flood." 9. ARBUTHNOT. 1 AP-PA-RÃ'-TUS, a complete set of instru-14 TRANS-CEND'-ENT, very excellent. ments for performing any operation. 5 GLEBE, soil; land. cays. 2 AS-CEND'-EN-CY, controlling influence; su-6 "WAXES AND WASTES," grows and deperiority. 3 COM-PACT'-ED, constructed; made dense 7 MOULD'-ER-ING, decaying. and firm. LESSON XVIII. ABUSES OF THE SKIN. 1. BUT what if those busy workers, the perspiration-tubes of which we have spoken, should stop laboring for only one day'? What if they should refuse to do the work which has been assigned to them? Would any injury be done'? Yes, a vast amount of injury. The waste particles of matter, when they are not permitted to escape through the pores of the skin, clog up the system, and irritate and poison it, so as to produce inflammation or fever. Only think of two or three pounds of waste and poisonous matter, that ought to be thrown away, collecting in the body in so short a time, merely because these little tubes are unable to do their work! If the difficulty should continue several days, and no remedy be found, not only disease, but death itself would be the result. 2. These perspiration-tubes are sometimes closed when a person takes a severe cold; for the cold, after deadening their action, contracts them, and closes the little pores which open on the skin. And now see how nature tries to remedy the evil. As the waste matter can not escape through these openings, it remains in the veins, but it clogs the current of the blood, and makes it a dark and filthy stream. This stream, with all its impurities, soon finds its way to the heart, and the heart sends it to the lungs to be cleansed. 3. But now the lungs have more work to do than usual, and, after toiling awhile with all their might to remove the impurities of the blood, they become weary; they themselves become clogged with the waste matter which they have separated from the blood; they make a vain effort, by coughing, to remove it, and then a fever sets in. There is now a fever all over the skin, and a fever in the lungs also, and all because the little pores of the skin stopped work for a while. The lungs did all they could to remove the evil, but the additional labor imposed upon them soon made them sick also. 4. We can scarcely imagine the amount of suffering caused by the closing up of these little pores-these millions of little breathing holes that are scattered all over the body. Closing them is like closing the mouth and nostrils, and shutting out the air we breathe. It.is vastly important, then, that we should know what dangers we are liable to from this source, and how we may avoid them. 5. A healthy action of the skin will be found to depend upon proper attention to clothing, cleanliness, exercise, light, and air. The importance of pure air is seen in the fact that the functions1 of the skin in purifying the blood are similar to those of the lungs. Light is as essential to an animal as to a plant. Plants that grow in the shade are never so strong and vigorous, nor have they so dark and brilliant colors, as those that grow in the sunshine; and a child that grows up in a dark cellar, or any dark room, will always have a pale and unhealthy countenance. 6. Although the skin requires a suitable degree of warmth, of which each person must be the judge in his own case, yet that kind of clothing should be used which is best adapted to protect the body from the effects of sudden changes of temperature. For this purpose woolen and cotton garments, fitting loosely, are to be preferred to linen, as the latter absorbs and retains moisture, and thereby rapidly conducts the heat from the body. 7. Any clothing of close texture3 that excludes air from the body, and thereby prevents the perspiration from passing off freely, is injurious; for if the poisonous matter be left in contact with the skin, it will be likely to be absorbed into the system by the lymphatics. Cover the body with varnish, so as to close the pores of the skin, and a feeling of suffocation will immediately be felt, a fever will set in, and the individual will soon die. India-rubber clothing that excludes the air will always produce injurious effects. The advantages of frequent ablutions of the whole body, and of frequent changes of clothing, arise from the importance not only of keeping the pores of the skin open and in healthy action, but also of preventing the absorption of the poisonous matter which has once been excluded by them. 8. But exercise in pure air is no less essential to the health of the skin than to other portions of the body. The capil laries of the skin depend for their vigorous action upon bodily exercise; the warmth of the skin, and the resistance which it offers to sudden changes of temperature, also depend upon that rapid waste and repair of the system, of which exercise is the immediate cause. And, finally, as a summary of all that may be said upon the subject of bodily health, its fundamental rules may be embraced in three words-TEMPERANCE, CLEANLINESS, and EXERCISE. 1 FUNC'-TIONS, offices; duties; employ-4 AB-LU'-TIONS, washings. 2 TEM'-PER-A-TŪRE (tem'-per-a-tyure), state 5 SUM'-MA-RY, a brief or abridged statement of a fuller account. 6 FUN-DA-MENT'-AL, most important; serving for the foundation. LESSON XIX. THE YEARS OF MAN'S LIFE. 1. THE first seven years of life—man's break of day— 2. From twenty-one proud manhood takes its date, 3. At forty-two his eyes grave wisdom wear, 4. At fifty-six cool reason reigns entire; Then life burns steady, and with temperate fire; |