IX. 



RESPIRATION. 



A. The Lungs of a Sheep. 



Materials. The lungs and trachea of a sheep. A glass of water. 

 Apparatus. Blowpipe. Twine. 



Study the lungs and trachea that have been reserved 

 from a former exercise. 



I. THE DIFFERENT PARTS. 

 Notice : 



a. The lungs. 



1. Their shape. 



2. Their size. 



3. Their color. 



4. Their weight as compared with water. Cut off 



a small piece and place in water. Explain 

 its action. 



b. The trachea. 



1. Its shape. 



2. Its size. 



3. The cartilaginous rings. What is their size, shape, 



and position. Do the rings reach entirely 

 around the trachea? Why? 



4. The lining membrane. 



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