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nerves enable us to feel any thing that we touch. These little pa-pil'-læ, filled with nerves, are like sentinels every where on duty, and they instantly send news to the brain when a part has been injured. In the tender and delicate parts of the system, which require the most care and protection, like the eye and the lungs, they are the most numerous. If a particle of dust lodges on the eyeball, how quickly do the nerves in the pa-pil'-læ send notice to the brain, that it may be removed! (See Fig. 16.)
LYMPHATICS.-9. In addition to the capillary blood-vessels and the nerves, the skin contains a system of tubular vessels called lym-phat-ics, or absorbents, which are so small that they can not be seen by the naked eye. The lymphatics open outwardly on the under surface of the cuticle or scarf-skin, while inwardly they open into the veins. Is it possible that these little vessels are of any use? Yes; and it is very certain that they have not been made in vain.
10. There is one thing, at least, which they are able to do. The mouths, or outward openings of the absorbents, are so exposed that substances placed upon the skin are taken up by them, carried along their little tubes, and emptied into the veins, whence they are carried to that great working engine, the heart, and then sent all over the system. It is very evident that if the substances thus absorbed by the lymphatics are good and useful to the system, they may benefit the whole body; but, if they are bad, they may do it a great amount of injury.
11. If the arm should be dipped in poison, what, probably, would be the result? The lymphatics would doubtless absorb the poison, and empty it into the veins, and the veins would carry it to the heart, and the heart would carry it to every part of the body, to every muscle, and bone, and sinew, and nerve, poisoning all; and death might be the result. Such cases have often happened.
12. The writer of this knew a person who, having washed a number of sheep in a decoction of tobacco to kill the vermin on them, was so poisoned by the juice of the tobacco that was taken up by the lymphatics of the hands and arms, and carried into the blood, that he was made sick, and con
fined to his bed for three months. In another case, several children in a family were actually killed by putting on their hands and arms a poisonous ointment by mistake. It is by the lymphatics that the poison from the bite of a mad dog, or a serpent, is carried into the system.
13. Physicians sometimes make use of the lymphatics to a very good purpose. In the process of vaccination," by which multitudes of lives are saved annually, a small particle of matter, placed under the outer skin, and being soon absorbed, affects the whole system, and protects it from the ravages of that terrible disease, the small-pox. Sometimes, when the stomach rejects a medicine, physicians give it by binding a quantity on the arm, after first removing the outer skin by a blister. It is also stated that persons have been fed through the skin, and kept alive for a long time by the absorption of nutritious substances.*
OIL-TUBES.-14. We have also said that the skin is full of oil-tubes. These draw oil from the blood, and spread it over the outer skin to keep the latter moist. In some parts of the body they are very abundant. Their little openings may be seen along the edges of the eyelids. The oil which they pour out there keeps the tears and moisture of the eyes within the lids, and also prevents that adhesion of the lids which occurs upon slight inflammation. These oil-tubes are also abundant on the head, where they supply the hair with a pomatum9 of Nature's own preparing.
1 MĚCH'-AN-ISM, machine work; the parts of a machine.
2 €ŎM'-PLI-¤Ã-TED, intricate; composed of many parts united.
3 EU-TI-CLE, the outer or scarf skin.
4 PUNO'-TŪRED, pierced.
5 TU-BU-LAR, having the form of a tube.
6 DE-COC'-TION, the liquor in which any
7 VAC-CIN-A-TION, the act of inoculating, or
9 PO-MA'-TUM, a perfumed ointment.
"A person who has abstained from water will, after he has immersed his body in a bath, not only find his weight increased, but the sensation of thirst abated."-DRAPER.
Fig. 17 is a representation of one of the perspiration-tubes, or sa-dor-ip'-arous glands, from the palm of the hand. The space from d to b represents a greatly magnified view of the thickness of the skin. The upper portion is the cuticle, the dark portion the colored layer, and the lower portion the true skin. The coil at the bottom, a, a, is imbedded in the surrounding fat, c, c. The tube opens on the surface of the skin, in a slight depression of the cuticle, at d.
Fig. 18 is a greatly magnified view of the surface of the skin of the palm of the hand. The dark lines are the furrows; the lighter portions are the ridges, in which are seen the dark circular openings of the perspiration tubes. Beneath these ridges are also the points of the pa-pil'- a læ, which we have described.
GROWTH AND DECAY-LIFE AND DEATH.
1. The most curious part of the skin is the numerous and minute PERSPIRATION-TUBES which it contains. These tubes open on the cuticle, and the openings are called pores of the skin. They descend into the true skin, where they form a coil, as seen in the drawing below. Small as are these tubes, they are lined on their inner surface with branches of the minute capillary blood-vessels, which we have described, and which are filled with the impure venous blood that is on its way back to the heart and lungs.
2. But what can be the object of all this complicated arrangement? Why are these little perspiration-tubes, as they are called, scattered thick all over the body-so thick, indeed, that thirty-five hundred of their little mouths have been counted on one square inch of the hand? What office have they to perform that is not performed by the capillaries, or the nerves, or the lymphatics, or the oil-tubes? Does there seem to be any necessity for them? Let us see.
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,
Waxes and wastes ; I call it mine', not me':
AP-PA-RA'-TUS, a complete set of instru- TRANS-CEND'-ENT, very excellent. ments for performing any operation. 5 GLEBE, soil; land. AS-CEND'-EN-CY, controlling influence; su-6 "WAXES AND WASTES," periority. 3 COM-PACT'-ED, constructed; made dense 7 MOULD'-ER-ING, decaying. and firm.
grows and de