232 THE ACUTE PNEUMONIAS 



also occur in the pleural exudation and effusion, and in the 

 lymphatics of the lung. The greatest number are found in the 

 parts where the inflammatory process is most recent, e.g., in an 

 area of acute congestion in a case of croupous pneumonia, and 

 therefore such parts are preferably to be selected for microscopic 

 examination, and as the source of cultures. When the inflam- 

 mation is resolving, some of the organisms often stain badly 

 {e.g., tend to lose the Gram-positive reaction) ; such individuals 

 are probably either dead or dying. Sometimes there occur in 

 pneumonic consolidation areas of suppurative softening, which 

 may spread diffusely. In such areas the pneumococci occur with 

 or without ordinary pyogenic organisms, streptococci being the 

 commonest concomitants. In other cases, especially when the 

 condition is secondary to influenza, gangrene may supervene and 

 lead to destruction of large portions of the lung. In these a 

 great variety of bacteria, both aerobes and anaerobes, are to be 

 found. 



In ordinary broncho-pneumonias also Fraenkel's pneunio- 

 coccus is usually present, sometimes along with pyogenic cocci ; 

 in the broncho-pneumonias secondary to diphtheria it may be 

 accompanied by the diphtheria bacillus, and also by pyogenic 

 cocci ; in typhoid pneumonias the typhoid bacilli or the b. coli 

 may be alone present or be accompanied by the pneumo- 

 coccus, and in influenza pneumonias the influenza bacillus may 

 occur. In septic pneumonias the pyogenic cocci in many cases 

 are the only organisms discoverable, but the pneumococcus may 

 also be present. Especially important, as we shall see, from the 

 point of view of the etiology of the disease, is the occurrence in 

 other parts of the body of pathological conditions associated 

 with the presence of the pneumococcus. By direct extension to 

 neighbouring parts, empyema, pericarditis, and lymphatic enlarge- 

 ments in the mediastinum and neck may take place ; in the first 

 the pneumococcus may occur either alone or with pyogenic cocci. 

 But distant parts may be affected, and the pneumococcus may 

 be found in suppurations and inflammations in various parts of 

 the body (subcutaneous tissue, peritoneum (especially in children), 

 joints, kidneys, liver, etc.), in otitis media, ulcerative endocarditis 

 (p. 217), and meningitis. In fact, there is practically no inflam- 

 matory or suppurative condition in the body in which the 

 pneumococcus in pure culture may not be found. These condi- 

 tions may take place either as complications of pneumonia, or 

 they may constitute the primary disease. The occurrence of 

 meningitis is of special importance, for next to the lungs the 

 meninges appear to be the parts most liable to attack by the 



