AND PHYSIOLOGY. 



219 



heart, but almost entirely pre- Fig. 22-2. 



vent its passage in an oppo- 

 site direction. They act in 

 the same manner as valves in 

 machinery, although with no 

 loss from friction, and conse- 

 quently no necessity of a lu- 

 bricating fluid. It was the 

 discovery of these valves in 

 the veins which led Harvey, 

 an English physician, to the 

 greater discovery of the cir- 

 culation of the blood. He in- 

 ferred that the blood could 

 pass in but one direction 

 through the veins, and conse- 

 quently in the opposite direc- 

 tion through the arteries. 



382. Inosculation — Use 

 of Anastomosis. — The arter- 

 ies and veins open into each 

 other (i. e., their own vessels) 

 very frequently, allowing a 

 ready flow of blood from one 

 vessel to the other, even if the 

 flow does not happen to be in the 

 most favorable direction from 

 the center of circulation to the 



The Superficial Veins on the Front of 

 the Upper Extremity. 1, Axillary Artery. 2, Axillary Vein. 3, Basilic Vein where 

 it enters the Axillary. 4, 4, Portion of the Basilic Vein which passes under the Brachial 

 Fascia — a portion of the Vein is freed from the Fascia. 5, Point where the Median Ba« 

 silic joins the Basilic Vein. 6, Points to the Posterior Basilic Vein. 8, Anterior Basilic 

 Vein. 9, Point where the Cephalic enters the Axillary Vein. 10, A portion of the sain* 

 Vein as seen under the Fascia ; the rest is freed from it. 11, Point where the Median 

 Cephalic enters the Cephalic Vein. 12, Lower portion of the Cephalic Vein. 13, Median 

 Cephalic Vein. 14, Median Vein. 15, Anastomosing Branch of the Deep and Superficial 

 Veins of the Arm. 16, Cephalica-Pollieis Vein. 17, Sub-Cutaneous Veins of the lin- 

 gers. IS, Sub-Cutaneous Palmar Veins. 



Who discovered the circulation of the blood? 



