172 Circulation of the Blood 



liver, in a living animal, which is easily done. You 

 will forthwith perceive the veins below the ligature 

 swelling in the same way as those of the arm when the 

 bleeding fillet is bound above the elbow ; a circum- 

 stance which will proclaim the course of the blood 

 there. And as you still seem to think that the blood 

 can regurgitate from the veins into the arteries by open 

 anastomoses, let the vena cava be tied in a living 

 animal near the divarication of the crural veins, and 

 immediately afterwards let an artery be opened to give 

 issue to the blood : you will soon observe the whole of 

 the blood discharged from all the veins, that of the 

 ascending cava among the number, with the single 

 exception of the crural veins, which will continue full ; 

 and this certainly could not happen were there any 

 retrograde passage for the blood from the veins to the 

 arteries by open anastomoses. 



