334 



THE HUMAN BODY 



The Course of the Blood. From what has been said it is clear 

 that the movement of the blood is a circulation. Starting from any 

 one chamber of the heart it will in time return to it; but to do this 



bas 



oep 



FIG. 106. The superficial veins in front of the elbow-joint. B', tendon of biceps 

 muscle; Bi, brachialis interims muscle; Pt, prpnator teres muscle; 1, median nerve; 

 2, 3, 4, nerve-branches to the skin; B, brachial artery, with its small accompany- 

 ing veins; cep, cephalic vein; bas, basilic vein; m', median vein; *, junction of a 

 deep-lying vein with the cephalic. 



it must pass through at least two sets of capillaries; one of these 

 is connected with the aorta and the other with the pulmonary 

 artery, and in its circuit the blood returns to the heart twice. 

 Leaving the left side it returns to the right, and leaving the right it 

 returns to the left; and there is no road for it from one side of the 



