117 



sions *." The pulmonary artery, which conveys the 

 venal blood from the right side of the heart, divides 

 into two branches, which are dispersed through the 

 substance of the lungs ; and its smaller branches, 

 running in the common cellular substance, become 

 at length inconceivably minute, forming at last a 

 /ilexus, or fine net-work, upon the proper cells .: and 

 they terminate afterwards, partly into exhalent ves- 

 sels, and partly into corresponding branches of the 

 pulmonary veins,. These veins, by frequent anasto- 

 mosis, diminishing in number and increasing in size, 

 form at last four large trunks, which finally deliver 

 the blood into the left side of the heart. From this 

 description, it is manifest, that, between the air con- 

 tained in the cells, and the blood flowing through 

 the vessels, are interposed the coats both of the cells 

 and vessels. When, therefore, air is said to enter 

 into the blood from the cells of the lungs, it must, 

 in some way, be conveyed through the coats of these 

 cells and blood-vessels. After what manner, there- 

 fore, is it able to effect a passage ? 



95. Every anatomist will allow, that the surface 

 of the cells of the lungs, like every other surface of 

 the body, is duly furnished with absorbent vessels, 

 of which not only the ordinary absorption of fluids 

 carried on by this surface, but the frequent remo- 

 vals of morbid matter from the bronchial cells, sup- 

 ply abundant proof. Mr Cruickshank has frequent- 

 ly seen the absorbents of the lungs turgid with blood 

 in cases of hcemoptoe, which blood they had ab- 



* Fyfe's Compendium of Anatomy, vol. ii. p. MS, 

 H 3 



