SYPHILIS OF THE LUNGS. 355 



acute inflammation may result from rupture of a tubercular 

 focus into the pleural cavity. In more chronic cases there 

 are almost constantly, extensive adhesions between the parietal 

 and visceral layers. 



Extension of the tubercular process in the lung itself is 

 caused by the aspiration of material from caseous foci to 

 other parts. Sputum loaded with tubercle bacilli is very 

 apt to infect the upper air-passages, and, if swallowed, the 

 gastro-intestinal tract. A general miliary tuberculosis may 

 result from secondary infection of the blood through tuber- 

 cular infiltration of the vessel- wall or rupture of a caseous 

 focus into its lumen. 



Pneumothorax is due to perforation of the pleura. The 

 pleura is very liable to undergo necrosis at a given point as 

 the result of an underlying focus of caseation in which are 

 involved the bloodvessels which nourish it. If this occurs 

 before pleuritic adhesions have been formed, perforation occurs. 

 In this manner are explained many cases in which an acute 

 pleurisy seems to precede the development of the pulmonary 

 affection. 



Fatal hemorrhage may result from erosion of one of the 

 branches of the pulmonary artery. 



Anaemia, emaciation, and fever are constant accompaniments 

 of phthisis. 



Widespread amyloid changes in the viscera are present in 

 a large number of cases. 



SYPHILIS OF THE LUNGS. 



Syphilitic inflammation of the lungs in adults is rare; though 

 gummata, appearing as grayish or yellowish rounded nodules, 

 are sometimes observed. They may undergo central necrosis, 

 and thus result in the formation of cavities. 



In congenital syphilis there is sometimes a consolidation of 

 extensive areas of lung-tissue, to which the term white pneu- 

 monia has been given, on account of the pale and anaemic 

 appearance of the affected areas. Microscopically there is 

 noted a great increase in the connective tissue, as in chronic 

 interstitial pneumonia, and a catarrhal exudate within the 

 alveoli. 



