46 PHYSIOLOGY FOR THE LABORATORY. 



the blood near the pump compare with the flow in the large 

 tube at the opposite end of the apparatus ? What is true 

 of the flowing of the blood in the large arteries and veins ? 



III. THE USE OF THE PERIPHERAL RESISTANCE. 



Material. AYater. A small force-pump. 



Apparatus. One metre of pure rubber tubing 12 m.m. in diameter. 



Connect with the pump a long piece of elastic rubber 

 tubing, and intermittently force water through it. Is the 

 outflow intermittent or continuous? Compare with the 

 result obtained when the peripheral resistance is present as 

 in II c. What is the effect of the peripheral resistance ? 

 What is the advantage of a continuous flowing of blood 

 in the body ? 



IV. THE USE OF THE ELASTIC WALLS OF THE TUBES. 



Material. Water. 



Apparatus. A small force-pump. 



50 c.m. of glass tubing 12 m.m. in diameter. 

 6 c.m. of rubber tubing 12 m.m. in diameter. 



Connect with the pump a piece of glass tubing, and 

 intermittently force water through it. Is the outflow in- 

 termittent or continuous? 



J. A Model to Show the Action of the Semilunar Valves. 



Material. A piece of thick manila paper, three inches by six and 

 a half inches, strong enough for sewing, and flexible enough to bend 

 easily. A piece of white cloth about the same size. Water. 



Apparatus. Two glasses. Needle and thread. 



A model of the base of the aorta and the semilunar 

 valves may be made of paper and cloth. The piece of 



