First Book in Physiology and Hygiene, J. H. Kellogg [pdf e book reader .TXT] 📗

Such air is unfit to breathe.

27. The Lungs Purify the Blood.—We have learned that the blood becomes dark in its journey through the body. This is because it loses its oxygen and receives carbonic-acid gas. While passing through the capillaries of the lungs, the blood gives out the carbonic-acid gas which it has gathered up in the tissues, and takes up a new supply of oxygen, which restores its scarlet hue.

28. How the Air is Purified.—Perhaps it occurs to you that with so many people and animals breathing all the while, the air would after a time become so filled with carbonic-acid gas that it would be unfit to breathe. This is prevented by a wonderful arrangement of Nature. The carbonic-acid gas which is so poisonous to us is one of the most necessary foods for plants. Plants take in carbonic-acid gas through their leaves, and send the oxygen back into the air ready for us to use again.

29. We have already learned that the oxygen taken in by the lungs is carried to the various parts of the body by the little blood corpuscles. The effect of strong liquors is to injure these corpuscles so that they cannot carry so much oxygen as they ought to do. For this reason, the blood of a drunkard is darker in color than that of a temperate person, and contains more carbonic-acid gas. The drunkard's lungs may supply all the air he needs, but his blood has been so damaged that he cannot use it. Excessive smoking has a similar effect.

SUMMARY.

1. Our bodies need air, just as a candle or a fire does.

2. A small animal shut up in a close jar soon dies for want of air. We need the oxygen which the air contains.

3. Oxygen causes a sort of burning in our bodies.

4. The burning in our bodies keeps us warm, and destroys some of the waste matters.

5. The breathing organs are the windpipe and bronchial tubes, the voice-box, the epiglottis, the nostrils, the soft palate, the lungs, the air-cells, the pleura, the diaphragm, and the chest walls.

6. When we breathe we use our lungs like a pair of bellows.

7. A man's lungs hold nearly one and a half gallons of air.

8. In ordinary breathing we use less than a pint of air, but when necessary we can use much more.

9. The air we breathe out contains carbonic-acid gas and another invisible poison.

10. A candle will not burn in air which has been breathed, and animals die when confined in such air.

11. The lungs purify the blood. While passing through the lungs, the color of the blood changes from purple to bright red.

12. Plants purify the air by removing the carbonic-acid gas.

13. Alcohol and tobacco injure the blood corpuscles so that they cannot take up the oxygen from the air which the lungs receive.

CHAPTER XIV. HOW TO KEEP THE LUNGS HEALTHY.

1. Pure Air Necessary.—A person may go without eating for a month, or without drinking for several days, and still live; but a strong man will die in a few moments if deprived of air. It is very important that we breathe plenty of pure air. There are many ways in which the air becomes impure.

2. Bad Odors.—Anything which rots or decays will in so doing produce an unpleasant odor. Bad odors produced in this way are very harmful and likely to make us sick. Many people have rotting potatoes and other vegetables in their cellars, and swill barrels, and heaps of refuse in their back yards. These are all dangerous to health, and often give rise to very serious disease. We should always remember that bad odors caused by decaying substances are signs of danger to health and life, and that these substances should be removed from us, or we should get away from them, as soon as possible.

3. Germs.—The chief reason why bad odors are dangerous is that they almost always have with them little living things called germs. Germs are so small that they cannot be seen by the naked eye: it takes a strong microscope to enable us to see them, but they are so powerful to do harm that if we receive them into our bodies they are likely to make us very sick, and they often cause death.

4. Contagious Diseases.—You have heard about diphtheria and scarlet fever and measles, and other "catching diseases." When a person is sick with one of these diseases, the air about him is poisoned with germs or something similar, which may give the same disease to other persons who inhale it. So when a person is sick from one of these diseases, it is very important that he should be put in a room by himself and shut away from every one but the doctor and the nurse. It is also necessary that all the clothing and bedding used by the sick person, and everything in the room, as well as the room itself, should be carefully cleansed and disinfected when the person has recovered, so as to wipe out every trace of the disease. The writer has known many cases in which persons who have been sick with some of these diseases were careless and gave the disease to others who died of it, although they themselves recovered. Do you not think it very wrong for a person to give to another through carelessness a disease which may cause his death?

5. Unhealthful vapors and odors of various sorts arise from cisterns and damp, close places under a house. Rooms which are shaded and shut up so closely that fresh air and sunshine seldom get into them should be avoided as dangerous to health.

6. Breath-Poisoned Air.—The most dangerous of all the poisons to which we are exposed through the air are those of the breath, of which we learned in a preceding lesson. We need plenty of fresh air to take the place of the air which we poison by our breath. Every time we breathe, we spoil at least half a barrelful of air. We breathe twenty times a minute, and hence spoil ten barrels of air in one minute. How many barrels would this make in one hour? We need an equal quantity of pure air to take the place of the spoiled air, or not less than ten barrels every minute, or six hundred barrels every hour.

7. Ventilation.—The only way to obtain the amount of fresh air needed, when we are shut up in-doors, is to have some means provided by which the fresh air shall be brought in and the old and impure air carried out. Changing the air by such means is called ventilation. Every house, and especially every sleeping-room, should be well ventilated. School-houses, churches, and other places where many people gather, need perfect ventilation. Ask your teacher to show you how the school-room is ventilated; and when you go home, talk to your parents about the ventilation of the house in which you live.

8. Many people ventilate their houses by opening the doors and windows. This is a very good way of ventilating a house in warm weather, but is a very poor way in cold weather, as it causes cold draughts, and makes the floor cold, so that it is difficult to keep the feet warm. It is much better to have the air warmed by a furnace or some similar means, before it enters the rooms. There ought also to be in each room a register to take the foul air out, so that it will not be necessary to open the windows. This register should be placed at the floor, because when the pure air enters the room warm, it first rises to the upper part of the room, and then as it cools and at the same time becomes impure, it settles to the floor, where it should be taken out by the register.

9. How to Breathe.—We should always take pains to expand the lungs well in breathing, and to use the entire chest, both the upper and the lower part. Clothing should be worn in such a way that every portion of the chest can be expanded. For this reason it is very wrong to wear the clothing tight about the waist. Clothing so worn is likely to cause the lungs to become diseased.

10. Bad Habits.—Students are very apt to make themselves flat-chested and round-shouldered by leaning over their desks while writing or studying. This is very harmful. We should always use great care to sit erect and to draw the shoulders well back. Then, if we take pains to fill the lungs well a great many times every day, we shall form the habit of expanding the lungs, and shall breathe deeper, even when we are not thinking about doing so.

11. Breathing through the Nose.—In breathing, we should always take care to draw the air in through the nose, and not through the mouth. The nose acts as a strainer, to remove particles of dust which might do harm if allowed to enter the lungs. It also warms and moistens the air in cold weather. The habit of breathing through the mouth often gives rise to serious disease of the throat and lungs.

12. Effects of Alcohol and Tobacco upon the Lungs.—Both alcohol and tobacco produce disease of the breathing organs. Smoking injures the throat and sometimes causes loss of smell. Serious and even fatal diseases of the lungs are often caused by alcohol.

13. Many people suppose that the use of alcohol will save a man from consumption. This is not true. A man may become a drunkard by the use of alcohol, and yet he is more likely to have consumption than he would have been if he had been a total abstainer. "Drunkard's consumption" is one of the most dreadful forms of this disease.

SUMMARY.

1. Pure air is as necessary as food and drink.

2. Anything which is rotting or undergoing decay causes a bad odor, and thus makes the air impure.

3. Foul air contains germs which cause disease and often death.

4. Persons sick with "catching" diseases should be carefully avoided. Such persons should be shut away from those who are well, and their rooms and clothing should be carefully cleansed and disinfected.

5. The breath poisons the air about us. Each breath spoils half a barrelful of air.

6. We should change the air in our houses, or ventilate them, so that we may always have pure air.

7. We should always keep the body erect, and expand the lungs well in breathing.

8. The clothing about the chest and waist should be loose, so that the lungs may have room to expand.

9. Always breathe through the nose.

10. Tobacco causes disease of the throat and nose.

11. Alcohol causes consumption and other diseases of the lungs.

CHAPTER XV. THE SKIN AND WHAT IT DOES.

1. The Skin.—The skin is the covering of the body. It fits so exactly that it has the precise shape of the body, like a closely fitting garment. If you will take up a little fold of the skin you will see that it can be stretched like a piece of india-rubber. Like rubber, when it is released it quickly contracts and appears as before.

2. The Bark of Trees.—Did you ever peel the bark off of a young tree? If so, you have noticed that there were really two barks, an outer bark, as thin as paper, through which you could almost see, and an inner and much thicker bark, which lay next to the wood of the tree. You can peel the outer bark off without doing the tree much harm. Indeed, if you will notice some of the fruit or shade trees in the yard, at home, you will see that the outer bark of the tree peels itself