THE CIRCULATION 



117 



exchanges with the lymph already described. The word 

 "capillary" means hair-like, but the description falls 

 far short of indicating the actual slenderness of these mi- 

 croscopic tubes. They are so narrow that the corpuscles 

 pass through them practically in single file. The capillar- 



Fig. 17. In this diagram, as is usual in such cases, right and left 

 are reversed. This is as though the observer were looking at an- 

 other subject. The short pulmonary path is to be traced from the 

 right ventricle to the left auricle (P. C.). Alternative routes are 

 suggested for the passage of the blood through the greater* circula- 

 tion from the left ventricle to the right auricle. The blood which 

 traverses the digestive tract (D) passes through a second set of 

 capillaries in the liver (L) before it can return to the heart. Note 

 that the liver has in addition a separate arterial supply of blood. 



ies are short and soon unite to form the smallest veins. 

 These lead the blood back toward the heart, joining as 

 they go to form larger and less numerous channels, until at 

 the last there are but two great veins. These enter the 

 right auricle, one from above and one from below. The 

 sweep of the blood from the left ventricle through the body 



