232 THE HUMAN BODY, 



steadily squeezing on the blood in them, forces it continu- 

 ously through the small arteries and capillaries. Thar 

 steady flow in the latter depends thus on two factors: first 

 the elasticity of the large arteries; and secondly the re- 

 sistance to their emptying, dependent upon internal friction 

 in the small arteries and the capillaries, which calls into 

 play the elasticity of the large vessels. Were the capillary 

 resistance or the arterial elasticity absent the blood-flow in 

 the capillaries would be rhythmic. 



