First Book In Physiology And Hygiene Part 3

Perhaps you have seen it burn in a lamp. It will burn without a lamp, if we light it. It is so clear and colorless that it looks like water. The Indians call it "fire-water." Alcohol differs very much from foods. It is not produced from plants, as fruits and grains are; neither is it supplied by Nature ready for our use, as are air and water.

~9. Fermentation.~--When a baker makes bread he puts some yeast in the dough to make it "rise," so the bread will be light. The yeast destroys some of the sugar and starch in the flour and changes it into alcohol and a gas. The gas bubbles up through the dough, and this is what makes the bread light. This is called _fermentation_ (fer-men-ta'-tion). The little alcohol which is formed in the bread does no harm, because it is all driven off by the heat when the bread is baked.

[Ill.u.s.tration: FERMENTATION.]

~10.~ Any moist substance or liquid which contains sugar will ferment if yeast is added to it, or if it is kept in a warm place. You know that canned fruit sometimes spoils. This is because it ferments. Fermentation is a sort of decay. When the juice of grapes, apples, or other fruit is allowed to stand in a warm place it "works," or ferments, and thus produces alcohol. Wine is fermented grape-juice; hard cider is fermented apple-juice.

~11.~ Beer, ale, and similar drinks are made from grains. The grain is first moistened and allowed to sprout. In sprouting, the starch of the grain is changed to sugar. The grain is next dried and ground, and is then boiled with water. The water dissolves the sugar. The sweet liquid thus obtained is separated from the grain, and yeast is added to it.

This causes it to ferment, which changes the sugar to alcohol. Thus we see that the grain does not contain alcohol in the first place, but that it is produced by fermentation.

~12.~ All fermented liquids contain more or less alcohol, mixed with water and a good many other things. Rum, brandy, gin, whiskey, and pure alcohol are made by separating the alcohol from the other substances.

This is done by means of a still, and is called _distillation_.

[Ill.u.s.tration: DISTILLATION.]

~13.~ You can learn how a still separates the alcohol by a little experiment. When a tea-pot is boiling on the stove and the steam is coming out at the nozzle, hold up to the nozzle a common drinking-gla.s.s filled with iced water, first taking care to wipe the outside of the gla.s.s perfectly dry. Little drops of water will soon gather upon the side of the gla.s.s. If you touch these to the tongue you will observe that they taste of the tea. It is because a little of the tea has escaped with the steam and condensed upon the gla.s.s. This is distillation.

~14.~ If the tea-pot had contained wine, or beer, or hard cider, the distilled water would have contained alcohol instead of tea. By distilling the liquid several times the alcohol may be obtained almost pure.

~15. Alcohol kills Animals and Plants.~--Strong alcohol has a deadly effect upon all living things. Once a man gave a dog a few tablespoonfuls of alcohol, and in a little while the dog was dead. If you should pour alcohol upon a plant it would die very soon.

~16.~ A man once made a cruel experiment. He put some minnows into a jar of water and then poured in a few teaspoonfuls of alcohol. The minnows tried very hard to get out, but they could not, and in a little while they were all dead, poisoned by the alcohol. A Frenchman once gave alcohol to some pigs with their food. They soon became sick and died.

~17. Alcohol not a Food.~--There are some people who imagine that alcohol is good for food because it is made from fruits and grains which are good for food. This is a serious mistake. A person can live on the fruits or grains from which alcohol is made, but no one would attempt to live upon alcohol. If he did, he would soon starve to death. In fact, men have often died in consequence of trying to use whiskey in place of food.

~18.~ We should remember, also, that people do not take alcohol as a food, but for certain effects which it produces, which are not those of a food, but of a poison.

~19.~ Many people who would not drink strong or distilled liquors, think that they will suffer no harm if they use only wine, beer, or cider.

This is a great mistake. These liquids contain alcohol, as do all fermented drinks. A person will become drunk or intoxicated by drinking wine, beer, or cider--only a larger quant.i.ty is required to produce the same effect as rum or whiskey.

~20.~ Another very serious thing to be thought of is that if a person forms the habit of drinking wine, cider, or other fermented drinks, he becomes so fond of the _effect they produce_ that he soon wants some stronger drink, and thus he is led to use whiskey or other strong liquors. On this account it is not safe to use any kind of alcoholic drinks, either fermented or distilled. The only safe plan is to avoid the use of every sort of stimulating or intoxicating drinks.

~21.~ It has been found by observation that those persons who use intoxicating drinks are not so healthy as those who do not use them, and, as a rule, they do not live so long.

~22.~ This is found to be true not only of those who use whiskey and other strong liquors, but also of those who use fermented drinks, as wine and beer. Beer drinkers are much more likely to suffer from disease than those who are strictly temperate. It is often noticed by physicians that when a beer-drinker becomes sick or meets with an accident, he does not recover so readily as one who uses no kind of alcoholic drinks.

~23.~ Alcoholic drinks not only make people unhealthy and shorten their lives, but they are also the cause of much poverty and crime and an untold amount of misery.

SUMMARY.

1. Water is the only thing that will satisfy thirst.

2. In going through our bodies, water washes out many impurities. We also need water to soften our food.

3. The purest water is the best. Impure water causes sickness.

4. Good water has no color, taste, or odor.

5. Tea and coffee are not good drinks. They are very injurious to children, and often do older persons much harm.

6. Alcohol is made by fermentation.

7. Pure alcohol and strong liquors are made by distillation.

8. Alcohol is not a food, it is a poison. It kills plants and animals, and is very injurious to human beings.

9. Even the moderate use of alcoholic drinks produces disease and shortens life.

CHAPTER VII.

HOW WE DIGEST.

~1.~ Did you ever see a Venus's fly-trap? This curious plant grows in North Carolina. It is called a fly-trap because it has on each of its leaves something like a steel-trap, by means of which it catches flies.

You can see one of these traps in the picture. When a fly touches the leaf, the trap shuts up at once, and the poor fly is caught and cannot get away. The harder it tries to escape, the more tightly the trap closes upon it, until after a time it is crushed to death.

[Ill.u.s.tration: VENUS'S FLY-TRAP.]

~2.~ But we have yet to learn the most curious thing about this strange plant, which seems to act so much like an animal. If we open the leaf after a few days, it will be found that the fly has almost entirely disappeared. The fly has not escaped, but it has been dissolved by a fluid formed inside of the trap, and the plant has absorbed a portion of the fly. In fact, it has really eaten it. The process by which food is dissolved and changed so that it can be absorbed and may nourish the body, is called _digestion_ (di-ges'-tion).

~3.~ The Venus's fly-trap has a very simple way of digesting its food.

Its remarkable little trap serves it as a mouth to catch and hold its food, and as a stomach to digest it. The arrangement by which our food is digested is much less simple than this. Let us study the different parts by which this wonderful work is done.

[Ill.u.s.tration: THE DIGESTIVE TUBE.]

~4. The Digestive Tube.~--The most important part of the work of digesting our food is done in a long tube within the body, called the _digestive tube_ or _ca.n.a.l_.

~5.~ This tube is twenty-five or thirty feet long in a full-grown man; but it is so coiled up and folded away that it occupies but little s.p.a.ce. It begins at the mouth, and ends at the lower part of the trunk.

The greater part of it is coiled up in the abdomen.

~6. The Mouth.~--The s.p.a.ce between the upper and the lower jaw is called the _mouth_. The lips form the front part and the cheeks the sides. At the back part are three openings. One, the upper, leads into the nose.

There are two lower openings. One of these leads into the stomach, and the other leads to the lungs. The back part of the mouth joins the two tubes which lead from the mouth to the lungs and the stomach, and is called the _throat_. The mouth contains the _tongue_ and the _teeth_.

[Ill.u.s.tration: THE TEETH.]

~7. The Teeth.~--The first teeth, those which come when we are small children, are called _temporary_ or _milk teeth_. We lose these teeth as the jaws get larger and the second or _permanent_ teeth take their place. There are twenty teeth in the first set, and thirty-two in the second. Very old persons sometimes have a third set of teeth.

[Ill.u.s.tration: SALIVARY GLANDS.]

~8. The Salivary~ (sal'-i-vary)~ Glands.~--There are three pairs of _salivary glands_. They form a fluid called the _saliva_ (sa-li'-va). It is this fluid which moistens the mouth at all times. When we eat or taste something which we like, the salivary glands make so much saliva that we sometimes say the mouth waters. One pair of the salivary glands is at the back part of the lower jaw, in front of the ears. The other two pairs of glands are placed at the under side of the mouth. The saliva produced by the salivary glands is sent into the mouth through little tubes called _ducts_.

~9. The Gullet.~--At the back part of the throat begins a narrow tube, which pa.s.ses down to the stomach. This tube is about nine inches long.

It is called the _gullet_, _food-pipe_, or _oesophagus_ (e-soph'-a-gus).

~10. The Stomach.~--At the lower end of the oesophagus the digestive tube becomes enlarged, and has a shape somewhat like a pear. This is the _stomach_. In a full-grown person the stomach is sufficiently large to hold about three pints. At each end of the stomach is a narrow opening so arranged that it can be opened or tightly closed, as may be necessary. The upper opening allows the food to pa.s.s into the stomach, the lower one allows it to pa.s.s out into the intestines. This opening is called the _pylorus_ (py-lo'-rus), or gate-keeper, because it closes so as to keep the food in the stomach until it is ready to pa.s.s out.