484 Pneumonia 



II. Bacillus pneumoniae (Friedlander) type which ferment all 

 carbohydrates except lactose, with formation of gas. 

 III. Bacillus lactis aerogenes type which ferment all carbohy- 

 drates except saccharose, with formation of gas. 

 Pathogenesis. — Friedlander found considerable difficulty in 

 producing pathogenic changes by 'the injection of his bacillus into 

 the lower animals. Rabbits and guinea-pigs were immune to its 

 action, and the only important pathogenic effects that Friedlander 

 observed occurred in mice, into whose lungs and pleura he injected 

 the cultures, with resulting inflammation. 



That Fri'edlander's bacillus may be the cause of true lobar pneu- 

 monia there can be no room for doubt after the demonstrations of 

 Lamar and Meltzer,* who found that its experimental introduction 

 into the bronchi of dogs was followed by true lobar pneumonia. The 

 lesions in thefee dogs, like those in human beings, were paler in color, 

 the lung tissue less friable, and the exudate more viscid than those 

 caused by the pneumococcus. 



Pneumonia in man, caused by Bacillus mucosus capsulatus, 

 is atypical clinically, very severe, and often fatal. 



Curry t found Friedlander's bacillus in association with the 

 pneumococcus in acute lobar pneumonia; in association with 

 the diphtheria bacillus in otitis media associated with croupous 

 pneumonia; and in the throat in diphtheria. In pure culture 

 it was obtained from vegetations upon the valves of the heart in 

 a case of acute endocarditis with gangrene of the lung; from the 

 middle ear, in a case of fracture of the skull with otitis media; and 

 from the throat in a case of tonsillitis. Zinsser has twice cultivated 

 Friedlander's bacillus from inflamed tonsils in children. 



Abel I cultivated it from the discharges of fetid ozena, and sup- 

 posed it to be the specific cause (Bacillus ozsenae). 



Occasionally Friedlander's bacillus bears an important relation- 

 ship to lobular or catarrhal pneumonia, an interesting case having 

 been studied by Smith. § The histologic changes in the lung were 

 remarkable in that the "alveolar spaces of the consolidated areas 

 were dilated and for the most part filled with the capsule bacilli. ' ' 

 In some alveoli there seemed to be pure cultures of the bacilli; others 

 contained red and white blood-corpuscles ; in some there was a Uttle 

 fibrin. The bacillus obtained from this case, when injected into the 

 peritoneal cavity of guinea-pigs, produced death in eleven hours. 

 The peritoneal cavity after death contained a large amount of thick, 

 slimy fluid; the intestines were injected and showed a thin fibrinous 

 exudate upon the surface; the spleen was enlarged and softened, and 

 the adrenals, much reddened. Cover-glass preparations from the 



* "Jour. Exp. Med.," 1912, xv, 133. 



t "Jour. Boston Sec. of Med. Sci.," March, 1898, vol. 11, No. 8, p. 137- 



% "Zeitschrift fiir Hygiene," xxi. 



§ "Jour. Boston Soc. of Med. Set.," May, 1898, vol. 11, No. 10. p. 174. 



