252 Pulmonary Artery ', s?<r. [Book IX* 



to the aorta, but the coats of which are lefs robuft. Its 

 trunk, having run upwards almoft as high as the aorta, 

 is divided into two parts, one of which paries under the 

 aorta to the right lung, while the other proceeds to the 

 left. Thefe arteries enter the lungs with the bronchia, 

 and the divilions and fub-divifions of both are diftri- 

 buted together through their fubftance. The ultimate 

 ramifications of the pulmonary artery are fpread oui on 

 the air-veflels, through which the blood undergoes that 

 change from the air which it is the purpofe of refpira- 

 tion to effeft. 



Befides receiving arteries in common with other parts 

 of the body, we find that the lungs continually receive 

 and return the fame quantity of blood as pafles 

 through all the other parts of the body i from which we 

 form fome idea of their extreme vafcularity. 



In the plate annexed (XII.) the arteries are repre- 

 fented freed from the mufcular and fibrous parts. 



1. Aorta afcendens. 



A. Three femilunar valves. 



2. Trunk of the coronary artery. 



3. Aorta defcendens. 



4. Subclavian artery. 



5.5. Carotid arteries. 



6.6. Vertebral arteries. 



7.7. Arteries that go to the lower part of the face, 



tongue, &c. 

 8 V 8. Temporal arteries. 



10.10. Trunks which go to the foramina narium, &c. 

 1 1. 1 1. Occipital arteries. 



12.12. Arteries wliich go to the fauces, &c. 

 B.B. A fmall portion of the bafis of the Ikull. 



13.13. Contorfions of the carotid arteries, before they 



pafs to the brain, 



C. The 



