500 



THE RESPIRATORY SYSTEM. 



INTERSTITIAL PNEUMONIA. 



This name is given to a chronic productive inflammation, which in- 

 volves the connective-tissue framework of the lung and the walls of the 

 air spaces, and results in the formation of new connective tissue and the 

 obliteration of the air spaces (Fig. 252). 



Such an interstitial pneumonia may follow acute lobar pneumonia 

 with the production of new intra-alveolar connective tissue, broncho- 

 pneumonia, chronic pleurisy, chronic bronchitis, and atelectasis, or may 

 be induced by the inhalation of the dust of coal, stone, or other inor- 

 ganic substances. Diffuse interstitial pneumonia may occur in syphilis. 



The topography of the lesion varies considerably in the different con- 

 ditions under which the new tissue growth occurs. If it follow acute 



FIG. 281.CHROXIC INTKRSTITIAL PXKUMOXIA. 



lobar pneumonia, one lobe or the whole of one lung may be involved and 

 covered with pleuritic adhesions. The lobe or the lung is small, smooth 

 on section, and firm in texture. The air spaces and small bronchi may 

 be largely obliterated by the new connective tissue. If it follow broncho- 

 pneumonia, one or more lobes are studded with fibrous nodules, which 

 correspond to the affected bronchi and the associated lung territory ; or 



Klipstein, Zeits. f. klin. Med., Bd. xxxiv., p. 191, 1898; also with special reference to 

 children, see Diirek, Deut. Arch. f. klin. Med., Bd. Iviii., p. 368, 1897. 



For a study of bacteria in the lungs of man and lower animals, see Beco, Arch, de 

 Med. experimentale, etc., t. xi., p. 318, 1899, and t. xiii., p. 551, 1901. 



For a study of experimental cooling of the body which may induce changes in the 

 blood, predisposing to infection with the pneumococcus, see Reineboth and Kohlhardt, 

 Deut. Arch. f. klin. Med., Bd. Ixv., p. 192, 1900. 



For a study of the effects of cooling in general as a predisponent to infection, see 

 Lode, Arch. f. Hygiene, Bd. xxviii., 1897, p. 344; also Kisskalt, Ibid., Bd. xxxix., p. 

 142, 1900, bibliography. 



For a study of the portals of entry in lung infection, with special reference to the 

 pleura, see Grober, Deutsch. Arch. f. klin. Med., Bd. Ixviik, p. 296, 1900, bibliography. 



For a recent comprehensive resume of bacteria in the lung, of the predisposing fac- 

 tors in pneumonia, and a summary with new studies of experimental pneumonia, see 

 Wadsworlh, Am. Jour. Med. Sci., vol. cxxvii., 1904. 



Concerning circulatory changes in the lungs under various pathological conditions, 

 see reference to Esser, p. 484. 



