198 The Lungs 



secondary to uterine disease. In the case of dyspepsia there is irri- 

 tation of the gastric filaments of the vagi, which, passing to the pul- 

 monary plexus, is reflected along the sympathetic filaments. An 

 asthmatic attack usually comes on suddenly, air being locked up in the 

 pulmonary vesicles, and the percussion-note becoming hyper-resonant. 

 Under the influence of an emetic, or of some special antispasmodic, the 

 muscular contraction yields, and air once more freely passes to and fro. 

 Though there is but little connective tissue in the healthy lung, as 

 the result of chronic interstitial pneumonia, or fibroid phthisis, large 

 quantities are formed, which ultimately undergo condensation and 

 atrophy (see cirrhosis of liver, p. 336). The disease may follow chronic 

 bronchitis, or may be due to the irritation caused by particles of coal 

 or grit (saw-grinder's phthisis). As the fibroid lung contracts, the walls 

 of the bronchi are dragged asunder and the tubes are dilated into enor- 

 mous cavities, under the atmospheric pressure (bronchiectasis : ppoyxos, 

 windpipe, eK-rao-o-co, draw out), the diaphragm rises, and the chest-walls 

 fall in. When the fluid which collects in these cavities is decomposed 

 it may be necessary to tap and drain them through the chest- wall. 



In extensive bronchiectases the right ventricle is hypertrophied 

 (p. 175), and the veins are full even to the tips of the fingers, which are 

 usually clubbed. 



Thus, in fibroid phthisis and in hepatic cirrhosis atrophy of the 

 new connective tissue ruins the"histological structure of, and obstructs 

 the flow of blood through, the viscus, but, whereas the cirrhotic liver 

 dwindles to insignificant proportions, the lung is unable to* do so, be- 

 cause, in obedience to the laws of atmospheric pressure, its exterior 

 must lie close to the parietal pleura. So great is the contracting force, 

 however, that, though the periphery of the lung cannot be pulled in- 

 wards, the bronchi, as just described, are widely stretched. The ' pull ' 

 continues in each case, but it is easier for contracting elements in the 

 lung to drag the walls of the bronchi towards the surface of the lung 

 than the surface of the lung towards the interior of the bronchi : so the 

 tubes are opened out into large cavities. 



In phthisis (0$to>, waste away) the lungs are small ; the chest as- 

 sumes the expiratory type, being low and flat ; the neck is long, because 

 the clavicle, the first rib, and the sternum have dropped ; and the ab- 

 dominal viscera hide in the phrenic dome. The shoulders are narrowed 

 and sloping, and the supra- and infra-clavicular regions are flat, on 

 account of the contracting fibrosis in the apices, and the percussion 

 note there is dull. 



In phthisis, as in emphysema, the capillary area of the lungs is 

 diminished, and the right ventricle grows large in its constant stni^iji* 

 to get its contents passed through the degenerate pulmonary area. 

 But the lungs, though poor, remain honest, and decline to send forth 

 blood which is of inferior quality. 



Branches of the pulmonary artery pass behind the bronchi to 



