THE CIRCULATION OF THE BLOOD 437 



people fancy, but it does not amount to much. A very 

 few years after his time, however, there was a Greek 

 philosopher, Erasistratus, who lived about three hundred 



THORACIC 

 DOCT. 



APPENDIX 



LEFT AURICUQ 



ARTERIES 



Fio. 1. The apparatus of the circulation, as at present known. The 

 capillary vessels, which connect the arteries and veins, are omitted, 

 on account of their small size. The shading of the " venous system " 

 is given to all the vessels which contain venous blood ; that of the 

 " arterial system ** to all the vessels which contain arterial blood. 



years before Christ, and who must have pursued anatomy 

 with much care, for he made the important discovery 

 that there are membranous flaps, which are now called 

 "valves," at the origins of the great vessels; and that 



