232 APPLIED PHYSIOLOGY 



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94. Hold a candle or lighted match near each crack of the room and 



notice that usually the flame is blown towards the inside from cracks 

 near the floor, while it is blown outward in cracks higher up. 



95. Clap two blackboard erasers together to make a small cloud of 

 dust, and watch the movements of the particles in a ray of sunlight, so 

 as to detect the direction of the air currents in the room. 



96. Show methods of ventilation by lowering the upper sash ; by 

 raising the lower and inserting a board in the opening. Show and 

 explain the methods of ventilation adopted in the school. 



REVIEW TOPICS 



I. Give the composition of the air. 



' 2. Describe ozone ; argon ; nature's method of removing 

 dust from inspired air ; and the dangers of inhaling 

 dust in certain trades. 



3. Tell how much oxygen is needed in the air to sustain 



life, and give a simple test to determine whether 

 sufficient is present. 



4. Give the effects of rarefied air, and air under increased 



pressure. 



5. Give the effects of carbonic acid gas. 



6. Describe foul air and its effects. 



7. Discuss the meaning and the effects of bad odors ; of 



sewer gas ; of night air ; and of cellar air. 



8. Describe 'malaria. 



9. Show how fire and lights contaminate the air. 



10. Describe coal gas poisoning. 



11. Show that foul air may contain disease germs. 



12. Calculate how much fresh air should be admitted into 



a given room for a given number of persons. 



13. Describe how ventilation naturally goes on, and tell 



some ways of assisting nature in ventilation. 



14. Tell how a schoolroom may be ventilated. 



15. Tell how the atmosphere is purified. 



