134 VARIATIONS IN VELOCITY. [BOOK i. 



diminished, while the pressure on the proximal (cardiac) side re- 

 mains at first .unaltered ; and this would necessarily cause an increase 

 in the rapidity of the stream through that artery. But, as we shall 

 see later on, from the complications of the vascular machinery 

 such problems as these become very intricate; and the results 

 of observations on variations in arterial velocity are not altogether 

 intelligible. It has been suggested that varying conditions of the 

 blood, by affecting the amount of adhesion between the blood and 

 the walls of the vessels, may be an important factor in determining 

 the variations in the velocity of the stream. 



