220 



PRACTICAL ANATOMY. 



conception reaches the ninth month of utcro-gestation, its blood is distributed 

 for purification in an organ called the placenta. This placenta, while structur- 

 ally very different from the lungs, accomplishes for the blood of the foetus just 



Right innominate vein 



Vena cava superior 

 Right pulmonary artery 



Vena cava inferior 



Left branch of portal vein 



DUCTUS VENOSUS 



Umbilical vein 



Portal vein 



Right branch of 

 portal vein 



Umbilical vein 

 Umbilical arteries 



Hypogastric artt 



Left innominate 

 vein 



1 rch of aorta 



DUCTUS ARTER10SUS 



Left pulmonary 

 artery 



Descending aorta 



Superior 

 mesenteric artery 



Splenic vein 



ffapitrtor 



mcst-nteric rein 



Inferior 

 mesenteric artery 



Left common iliac 

 artery 



Internal iliac artery 



External ilincarlfry 



FIG. 155. THE HEART, WITH THE ARCH OF THE AORTA, THE PULMONARY ARTERY, THE Durirs 

 ARTERIOSUS, AND THE VESSELS CONCERNED IN THE FCETAL CIRCULATION. 

 (From a preparation of a foetus in the Museum of St. Bartholomew's Hospital.) 



the same results as are accomplished by the lungs post partcm. The purification 

 of the blood in either case is in accordance with the law of physics regulating 

 the diffusion of gases. Blood, on entering lung or placenta, is laden with CO./; 



