278 



THE VITAL FUNCTIONS. 



vided for each. There are, in fact, two hearts ; 

 the one on the left side impelling the blood 

 through the greater, or systemic circulation ; 

 the other, on the right side, appropriated to the 

 lesser, or pulmonary circulation. The annexed 



diagram (Fig. 359), il- 

 lustrates the plan of the 

 circulation in warm- 

 blooded animals. From 

 the left ventricle (l) the 

 blood is propelled into 

 the aorta (a), to be dif- 

 fused through the arte- 

 ries of the system (b) to 

 every part, and pene- 

 trating into all the capil- 

 lary vessels ; thence it 

 is returned by the veins, through the vense cavae 

 (c), to the right auricle (d), which delivers it 

 into the right ventricle (e). This right ventricle 

 impels the blood, thus received, through the 

 pulmonary arteries (f), into the lungs (at h), 

 where it is aerated, and whence it is recon- 

 veyed by the pulmonary veins (i), into the left 

 auricle (k), which immediately pours it into the 

 left ventricle (l), the point from whence we 

 set out. 



Both the right and the left heart have their 

 respective auricles and ventricles ; but they are 

 all united in one envelope, so as to compose 



