164 



THE LYMPHATICS OF THE LUNG. 



but chiefly from the lymph-canalicular system of the pleural alveoli. Some of these branches 

 proceed to the bronchial glands, but others pass into the interlobular septa, where they join (b) 

 the peri-vascular lymphatics which arise in the lymph-canalicular system of the alveoli. These 

 trunks, provided with valves, run alongside the pulmonary artery and vein, and in their course 

 they form frequent anastomoses. Special vessels arise within the walls of the bronchi, and occur 

 chiefly in the outer coat of the latter, constituting (c) the peri-bronchial lymphatics, which 

 anastomose with b. The branches of these two sets run towards the bronchial glands. Not 

 unfrequently (cat) masses of adenoid tissue are found in the course of these lymphatics.] The 

 lymph-canalicular system and the lymphatics become injected when fine-coloured particles are 

 inspired, or are introduced into the air-cells artificially. The pigment particles pass through 

 the semi-fluid cement-substance into the lymph-canalicular system and thence into the lym- 

 phatics ; or, according to Klein, they 

 pass through actual holes or pores in 

 the cement (p. 162).] [This pigmenta- 

 tion is well seen in coal-miner's lung or 

 anthracosis, where the particles of car- 

 bon pass into and are found in the 

 lymphatics. Sikorski and Kiittner 

 showed that pigment reached the lym- 

 phatics in this way during life. If 

 pigment, China ink, or indigo-carmine 

 be introduced into a frog's lung, it is 

 found in the lymphatic system of the 

 lung. Ruppert, and also Schotielius, 

 showed that the same result occurred 

 in dogs after the inhalation of charcoal, 

 cinnabar, or precipitated Berlin blue, 

 and von Ins after the inhalation of 

 silica. Schestopal used China ink and 

 cinnabar suspended in per cent, salt 

 solution.] Excessively fine lymph- 

 canals lie in the wall of the alveoli in 

 the interspaces of the capillaries, and 

 there are slight dilatations at the points 

 of crossing. According to Pierret and 

 Renaut every air-cell of the lung of the 

 ox is surrounded by a large lymph- 

 space, such as occurs in the salivary 

 glands. "When a large quantity of fluid 

 is injected into the lung, it is absorbed 

 with great rapidity ; even blood-cor- 

 puscles rapidly pass into the lym- 

 phatics. 



The superficial lymphatics of the 



pulmonary pleura communicate with 



Fig. 133. the pleural cavity by means of free 



Human lung ( x 50 and reduced ). a, small bronchus ; openings or stomata, and the same is 



b, b, pulmonary artery ; c, pulmonary vein ; e, inter- true of tne lymphatics of the parietal 



lobular septa, continuous with the deep layer of the pleura, but these stomata are confined 



pleura p. t0 limited areas over the diaphragmatic 



pleura. [The lymphatics in the costal 

 pleura occur over the intercostal spaces and not over the ribs (Dybkowski).] The large arteries 

 of the lung are provided with lymphatics which lie between the middle and outer coats. [The 

 movements of the lung during respiration are most important factors in moving the lymph 

 onwards in the pulmonary lymphatics. The reflux of the lymph is prevented by the presence 

 of valves.] 



[The nerves of the lung are derived from the anterior and posterior pulmonary plexuses, and 

 consist of branches from the vagus and sympathetic. They enter the lungs and follow the dis- 

 tribution of the bronchi, several sections of nerve-trunks being usually found in a transverse 

 section of a large bronchial tube. The nerves lie outside the cartilages, and are in close relation 

 with the branches of the bronchial arteries. Medullated and non-medullated nerve-fibres occur 

 in the nerves, which also contain numerous small ganglia (Eemak, Klein, Stirling). In the 

 lung of the calf the ganglia are large. The exact mode of termination of the nerve-fibres 

 within the lung has yet to be ascertained in mammals, but some fibres pass to the bronchial 

 muscle, others to the large blood-vessels of the lung, and it is highly probable that the mucous 

 glands are also supplied with nerve-filaments. In the comparatively simple lungs of the frog, 

 nerves with numerous nerve-cells in their course are found {Arnold, Stirling), and in the very 



