~4. An Interesting Experiment.~--We have told you that all fermented drinks contain alcohol. You will remember that wine, beer, ale, and cider are fermented drinks. We know that these drinks contain alcohol because the chemist can separate the alcohol from the water and other substances, and thus learn just how much alcohol each contains. ~5.~ If we should remove all the alcohol from wine, no one would care to drink it. The same is true of beer and cider. It is very easy to remove the alcohol by the simple process of heating. This is the way the chemist separates it. The heat drives the alcohol off with the steam. If the heating is continued long enough, all the alcohol will be driven off. The Chinaman boils his wine before drinking it. Perhaps this is one reason why Chinamen are so seldom found drunken. ~6.~ By a simple experiment which your parents or your teacher can perform for you, it can be readily proven that different fermented drinks contain alcohol, and also that the alcohol may be driven off by heat. Place a basin half full of water upon the stove where it will soon boil. Put into a glass bottle enough beer or cider so that when the bottle stands up in the basin the liquid in the bottle will be at about the same height as the water in the basin. Now place in the neck of the bottle a closely fitting cork in which there has been inserted a piece of the stem of a clay pipe or a small glass tube. Place the bottle in the basin. Watch carefully until the liquid in the bottle begins to boil. Now apply a lighted match to the end of the pipe-stem or glass tube. Perhaps you will observe nothing at first, but continue placing the match to the pipe-stem, and pretty soon you will notice a little blue flame burning at the end of the stem. It will go out often, but you can light it again. This is proof that alcohol is escaping from the liquid in the bottle. After the liquid has been boiling for some time, the flame goes out, and cannot be re-lighted, because the alcohol has been all driven off. [Illustration: Alcohol experiment.] ~7. The Alcohol Breath.~--You have doubtless heard that a person who is under the influence of liquor may be known by his breath. His breath smells of alcohol. This is because his lungs are trying to remove the alcohol from his blood as fast as possible, so as to prevent injury to the blood corpuscles and the tissues of the body. It is the vapor of alcohol mixed with his breath that causes the odor. ~8.~ You may have heard that sometimes men take such quantities of liquor that the breath becomes strong with the vapor of alcohol and takes fire when a light is brought near the mouth. These stories are probably not true, although it sometimes happens that persons become diseased in such a way that the breath will take fire if it comes in contact with a light. Alcohol may be a cause of this kind of disease.