1 Mixed Pneumonias 461 



tion of the antrum of Highmore and frontal sinuses, endometritis, 

 perirenal abscesses, and peritonitis. 



Virulence. The virulence of the organism seems to vary under 

 different conditions. It is sometimes harmless for the experiment 

 animals, but when injected into mice and guinea-pigs usually pro- 

 duces local inflammatory lesions, and sometimes death from septic 

 invasion. 



CATARRHAL PNEUMONIA OR BRONCHO -PNEUMONIA 



This form of pulmonary inflammation occurs in local areas, commonly situated 

 about the distribution of a bronchiole. It cannot be said to have a specific 

 micro-organism, as almost any irritating foreign matter accidentally inhaled 

 may cause it. The majority of the cases, however, are infectious in nature and 

 result from the inspiration, from higher parts of the respiratory apparatus, of 

 the staphylococci and streptococci of suppuration, Friedlander's bacillus, the 

 bacillus of influenza, and other well-known organisms. 



TUBERCULOUS PNEUMONIA 



The progress of pulmonary tuberculosis is at times so rapid that the tubercle 

 bacilli are distributed with the softened infectious matter throughout the entire 

 lung or to large parts of it, and a distinct pneumonic inflammation occurs. Such 

 a pneumonia may be caused by the tubercle bacillus, or the tubercle bacillus 

 together with staphylococci, streptococci, tetragenococci, pneumpcocci, pneu- 

 mobacilli, and other organisms accidentally present in a lung in which ulceration 

 and cavity formation are advanced. 



PLAGUE PNEUMONIA 



The pneumonic form of plague is characterized by consolidation of the lung 

 histologically and anatomically, indistinguishable from pneumococcic and 

 other extensive pulmonary infections. 



MIXED PNEUMONIAS 



It frequently happens that pneumonia occurs in the course of influenza or 

 shortly after convalescence from it. In these cases a mixed infection by the 

 influenza bacilli and pneumococci is commonly found. Sometimes pneumococci 

 and staphylococci simultaneously affect the lung, purulent pneumonia with 

 abscess formation being the conspicuous feature. Almost any combination 

 of bacteria may occur in the lungs, so that it must be left for the student to work 

 out what the particular effects of each may be. 



Among the mixed forms of pneumonia may be mentioned those called by 

 Klemperer and Levy "complicating pneumonias," occurring in the course of 

 typhoid fever, etc. 



