SECT. 178.] VESSELS AND NERVES OF THE LUNGS. 389 



panying the bronchia. Small independent vessels, which do not 

 arise from the bronchial arteries, may also be traced along the 

 pulmonary ligaments to the pleura. 



The lymphatics of the lung are very numerous. The superficial 

 ones run in the subserous connective tissue, in the interspaces of the 

 larger and smaller lobules, and form a network, of which the super- 

 ficial meshes are finer; and the deeper, coarser and angular. This 

 plexus covers the whole surface of the lung, and discharges itself 

 by means of special superficial trunks, which converge to the root 

 of the lung, following the course of the blood-vessels; and the 

 superficial plexus has also a connexion with the deeper vessels by 

 means of numerous trunklcts, which pass inwards between the 

 lobules. These deeper lymphatics arise from the walls of the 

 bronchia and blood-vessels, especially those of the pulmonary 

 arteries, and run with these canals through the pulmonary sub- 

 stance, and through some small lymphatic glands (glandulce pul- 

 monale s), to the root of the lung, where they join the larger 

 bronchial glands. 



The nerves of the lungs arise from the vagus and sympathetic, 

 form the small anterior and the large posterior pulmonary plexuses, 

 and are especially distributed with the bronchia and the pulmonary 

 artery, although here and there they also accompany the pulmonary 

 veins and the bronchial vessels. They are furnished with micro- 

 scopic ganglia in the interior of the lung, and can be followed to 

 near the terminations of the bronchial tubes. 



It is worthy of observation, that in addition to the air-vesicles, some other 

 parts in the lungs are supplied by the pulmonary vessels, viz., the surface of 

 the lung and the Ji?ier bronchia. With regard to the former, there are seen at 

 different places, upon an uninjected lung, small branches of the pulmonary 

 artery passing to the surface of the lung, and ramifying beneath the pleura. 

 Reixseisen (p. 17) describes these vessels, and gives very beautiful drawings of 

 them (tab. iv. v.) ; and recently, Adriani has followed them in injected lungs, 

 and states that they describe a tortuous course and frequently anastomose, 

 being here considerably thicker, and forming wider networks than the vessels 

 of the alveoli. The blood of these networks is drawn off by superficial roots 

 of the pulmonary veins on the one hand, and on the other hand, by anasto- 

 moses with the expansion of the bronchial vessels on the pulmonary pleura. 

 That the pulmonary arteries also supply the bronchia in part, had been already 

 mentioned by Arnold (Anat.ii. 171); and we are indebted to Adriani for 

 more particular information on this interesting subject. According to him 

 the pulmonary arteries and the pulmonary veins are the vessels chiefly con- 

 cerned in the formation of the capillary network on the surface of the bronchia. 

 This plexus is distinguished by the elongated form of its meshes, while its 

 vessels are almost as narrow as on the air-cells, measuring in man 0-004"' to 

 o-oo6"' in diameter. The bronchial vessels in this situation appear to supply 



