104 



PHYSIOLOGY AND HEALTH. 



in each lung, and then join together and enter the auricle 

 on the left side of the heart. 



FIG. XIV. Double Circulation of the Blood. 



The arrows show the course of the blood. 



226. These two sets of vessels constitute what is called the 

 double circulation. The J^lood is in the left auricle, (Fig 

 XIV. a,) and passes thence downward to the left ventricle, 



