228 NATURE STUDY REVIEW [8 :6— Sept., 1912 



(a). Take a record in seconds of the longest time each 

 pupil can say "ah", using as little force as possible in doing this. 

 Compare these times with corresponding capacities. 



(b). Exhale through a glass tube into a glass fruit jar and 

 when the jar has been filled with exhaled air invert it over a 

 short, burning candle. At the same moment invert another 

 similar jar with fresh air over another burning candle. Note the 

 relative time the candles continue to burn. 



(c). Get a number of small vials just big enough to hold 

 large-sized locusts (commonly called grasshoppers). Select pairs 

 of locusts of equal size and put each locust in a vial. The vial 

 for one locust of each pair should be filled with exhaled air and 

 then both should be corked and laid aside for a number of hours. 

 Note the relative time when the menibers of each pair cease to 

 be inactive (quit breathing) and if possible remove each from 

 the vial at that moment and note what happens after a short time. 



(d). Let each pupil fill a wide-mouthed bottle with his own 

 breath by breathing into it through a glass tube. Cork the bottles 

 and let stand till the pupils come in fresh from vigorous outdoor 

 play. Now explain that if the breath in the bottle has a bad odor 

 on being smelled it is generally a sign of decayed teeth or some- 

 thing like that. Let the pupils now smell the bottles but do not 

 ask for reports. [The teacher should know that carbon dioxide is 

 practically odorless, and that the bad odors of inhabited rooms 

 come chiefly from unclean skin and clothing.] 



(B). Sonic Hygienic Conclusions. 



In the light of the experiments indicated above (and others 

 that may occur to the teacher) and before any book study has 

 been indulged in, consider with the pupils such questions as the 

 following : 



Of two boys the same size but of different lung capacities, 

 which do you think could run the longest distance or climb the 

 greater number of stair-steps without running out of wind? 

 Give reasons for sitting erect in one's seat. What do you notice 

 about the chests and shoulders of the finest looking men and wo- 

 men you meet on the street or highway? Do you suppose a boy 

 or girl could get a larger chest if he tried? What do you think 

 one could do to have a larger chest and lungs ? Shall we all "test 

 our lungs" again alx)ut once a week to see who can make the 

 greatest improvement ? 



How do we know that the air we breathe out is different 

 from that we take in ? Do you think it is poisonous ? ( Popular 



