118 LABORATORY MANUAL 



number? In size? The smaller are called red cor- 

 puscles. How are they arranged? Can you make out 

 their shape? Make two drawings of a red corpuscle, 

 one as seen on end, the other from the side. 



The larger bodies are the white corpuscles. Describe 

 them. 



CHAPTER XX 



RESPIRATORY SYSTEM 



Exercise 79. Respiratory Organs and Mechanics of 

 Respiration. (Demonstration.) 



Object: To study the organs and mechanics of 

 respiration. . 



Apparatus 



Chart or plaster model Sheet rubber 



Skeleton Rubber balloon 



Mechanical device for rib action Glass tube 

 Belljar with stopper 



Directions: A. The lungs are the chief organs of 

 respiration. The structure of the lungs was studied 

 in Exercise 77, in the study of the beef "pluck." Note 

 on the chart or plaster model their position in the 

 body. The cavity in which the lungs and heart are 

 found is the thorax. On the skeleton note the bones 

 forming the frame work of this cavity. The floor of 

 the thorax is a muscular sheet called the diaphragm. 

 Note on the skeleton the attachment of the ribs to the 

 sternum by means of cartilage. This permits the 



