CHAPTER VIII. 



INFLAMMATORY AND SUPPURATIVE CONDITIONS, 

 CONTINUED: THE ACUTE PNEUMONIAS, EPI- 

 DEMIC CEREBRO-SPINAL MENINGITIS. 



Introductory. — The term Pneumonia is applied to several con- 

 ditions which present differences in pathological anatomy and in 

 origin. All of these, however, must be looked on as varieties of 

 inflammation in which the process is modified in different ways, 

 depending on the special structure of the lung or of the parts 

 which compose it. There is, first of all — and, in adults, the com- 

 monest type — the acute croupous or lobular pneumonia, in which 

 an inflammatory process attended by abundant fibrinous exuda- 

 tion affects, by continuity, the entire tissue of a lobe or of a 

 large portion of the lung. It departs from the course of an 

 ordinary inflammation in that the reaction of the connective 

 tissue of the lung is relatively slight, and there is usually no 

 tendency for organisation of the inflammatory exudation to 

 take place. Secondly, there is the acute catarrhal or lobular 

 pneumonia, where a catarrhal inflammatory process spreads from 

 the capillary bronchi to the air vesicles, and in these, changes, 

 consisting on the one hand of capillary bronchitis with aspira- 

 tion of the exudate into the alveoli and on the other of prolifera- 

 tion of the endothelium of the alveoli, take place which lead to 

 consolidation of patches of the lung tissue. Up till 1889 acute 

 catarrhal pneumonia was comparatively rare except in children. 

 In adults it was chiefly found as a secondary complication to 

 some condition such as diphtheria, typhoid fever, etc. Since, 

 however, influenza in an epidemic form has become frequent, 

 catarrhal pneumonia has been of much more common occurrence 

 in adults, has assumed a very fatal tendency, and has presented 

 the formerly quite unusual feature of being sometimes the pre- 

 cursor of gangrene of the lung. Besides these two definite types 

 other forms also exist. Thus insteadpf a fibrinous material the 

 exudation may be of a serous, hemorrhagic, or purulent char- 



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