THE CIRCULATION OF THE BLOOD. 43 



H. Experiments on the Student's Body. 

 Apparatus. A watch. A rubber band, or piece of twine. 



1. Find the pulse in different places. 



a. In the wrist. 



b. In the thumb. 



c. In front of the ear, or the side of the face. 



d. Under the knee. Cross one knee over the other and 

 watch the foot of the crossed knee. Explain. 



e. On the temple. 



2. Count your pulse standing, sitting, lying down, and 



after running. How soon is the pulse normal after 

 running ? 



3. Trace the veins and arteries on the back of the hand 



and in the wrist. How can you distinguish between 

 the veins and the arteries? 



4. Tie a rubber band tightly around your finger. Ex- 



plain the result. 



5. Press with a finger on the skin, and then lift the finger. 



6. Listen for the sounds of the heart of another person. 



I. The Demonstration of the Principles of Circulation. 

 I. UPON WHAT CIRCULATION DEPENDS. 



a. The beat of the heart. 



b. The peripheral resistance, or the resistance to the 



flowing of the blood in the capillaries. 



c. The long stretch of elastic tubing or blood-vessels. 



