RESPIRATION AND THE VOICE. 1*21 



CHAPTER VIII. 

 RESPIRATION AND THE VOICE. 



SECTION I. Air. 1. We have studied the processes of 

 digestion and absorption, by which food and water get . 

 into the blood, to be distributed through the body. It 

 remains to study the method by which air is taken in and 

 used. The process is called respiration. 



2, We live in air, and we can not live out of it any 

 more than fishes can live out of water. We can not see 

 the air, but we can feel it. When it is moving very 

 rapidly, it has great force. It can root up trees, and 

 carry away houses. If we could see it, it would appear 

 like water. When the wind is blowing, we would see a ( 

 stream of it pouring across the country like a river, or 

 like a flowing sea. 



SUGGESTIONS TO TEACHERS. SECTION I. A few chemical experiments 

 will illustrate this section. Show the effect of oxygen and of carbonic-acid 

 gas on a burning candle. Fill a test-tube with lime-water, and breathe into 

 it to demonstrate carbonic-acid gas by the formation of a milky precipitate 

 of carbonate of lime. 



SECTION II. Show, if possible, a fish's gills. Illustrate by drawings; 

 by a bunch of grapes, etc. Get a piece of lung from the butcher's, or, still 

 better, the lungs and air-passages of some small animal. 



SECTION III. The nasal cavities should be shown, either in the human 

 skull, or in that of a sheep or other animal. 



SECTION IV. Simple experiments with the apparatus mentioned in the 

 text, will illustrate the principles. 



SECTION VI. Show the moisture in the breath by breathing on glass. 



SECTION VII. A larynx can easily be got from a butcher, and the glottis 

 and vocal cords and muscles can be shown. 



