14 LABORATORY LESSONS IN GENERAL SCIENCE 



6. That the lungs may be able to perform their work 

 (function) well, and make use of the available oxygen, in 

 what condition must the tissues of all their parts be ? What 

 in general are the two requisites for the healthy condition of 

 any organ of the body? Why is a diseased state of the 

 lungs less likely in a person who leads an active out-of-door 

 life? What is tuberculosis of the lungs? 



RESPIRATION 



1. With the hands held firmly against the chest walls 

 at the sides, take several deep breaths. Describe in a 

 general way what motions of the walls are noted. What 

 name is given that part of the breathing process in which 

 air (a) goes into the lungs ; (6) is expelled from the lungs ? 



2. Name in order the principal passage- 

 ways through which air goes on its way to 

 the lungs. 



3. Compare the movements of air pass- 

 ing into and out of the chest during respira>- 



tion, and into and 

 out of an accordion 

 while being played. 



4. Sitting erect 

 and in a comfort- 

 able position, count 

 the number of ex- 

 halations per minute 



FIG. 8. Using a spirometer to test lung capacity. 



in your breathing. 



5. Fill a gallon jug with water, and close with a stopper. 

 Let the teacher invert the jug, and with its mouth under 



