Chap. 25.] [ 255 ] 



CHAP. XXV. 



GENERAL DISTRIBUTION OF THE VEINS, 



pulmonary Veins.-~Vena Ca-va. Veins of the Head, "Jugular an& 

 Subcla~uian. Feins of the Superior Extremity. Vena Axygos. 

 Veins of the Lower Extremities. Courfe of the BUod through the 

 abdominal Vifcera, the Liver, &c, 



IN defcribing the arteries we followed the courfe of 

 the blood, and beginning with the largeft trunks, 

 traced the feveral branches in the crder in which they 

 were fent off. In pointing out the courfe of the veins, 

 however, and ftill following the courfe of their contents, 

 the order of the defcription will neceflarily be reverfed, 

 as it is neeeffary, in this cafe, to begin with the rami- 

 fications, and trace them into the trunks. 



'The veins of the body may be divided into two 

 claflfes ; thofe which return the blood conveyed by the 

 pulmonary artery, and thofe which return that of the 

 aorta. 



It has been already remarked, that, befides the blood 

 which the lungs receive in common with other parts 

 of the body, they alfo receive all that is tranfmitted by 

 the pulmonary artery. This, after being diftributed 

 through the fubftance of the lungs, is returned by 

 veins, which at length unite into four trunks, and 

 paffing through the pericardium, are inferted into the 

 pofterior auricle of the heart. 



The blood, which is fent to the various parts of the 

 body by the aorta is ultimately received and returned 

 by two large trunks, the vena cava fuperior and infe- 

 rior, which enter the anterior auricle of the heart. I 



ihali 



