204 THE ACUTE PNEUMONIAS 



"nail-like" which has been applied. Occasionally bubbles of 

 gas develop along the line of growth. There is no liquefaction 

 of the medium. On sloped agar it forms a very white growth 

 with a shiny lustre, which, when touched with a platinum needle, 

 is found to be of a viscous consistence. In cultures much longer 

 rods are formed than in the tissues of the body (Fig. 70). On 

 the surface of potatoes it forms an abundant moist white layer. 

 Friedlander's bacillus has active fermenting powers on sugars, 

 though varieties isolated by different observers vary in the degree 

 in which such powers are possessed. It always seems capable 

 of acting on dextrose, lactose, maltose, dextrin, and mannite, and 

 sometimes also on glycerin. The substances produced by the 

 fermentation vary with the sugar fermented, but include ethylic 

 alcohol, acetic acid, laevolactic acid, succinic acid, along with 

 hydrogen and carbonic acid gas. The amount of acid produced 

 from lactose seems only exceptionally sufficient to cause coagula- 

 tion of milk. It is said by some that this bacillus is identical 

 with an organism common in sour milk, and also a normal 

 inhabitant of the human intestine, viz. the bacterium lactis 

 aerogenes of Escherich. 



The Occurrence of the Pneumobacteria in Pneumonia and 

 other Conditions. Capsulated organisms have been found in 

 every variety of the disease in acute croupous pneumonia, in 

 broncho-pneumonia, in septic pneumonia. In the great majority 

 of these it is Fraenkel's pneumococcus which both microscopic- 

 ally and culturally has been found to be present. Friedlander's 

 pneumobacillus occurs in only about 5 per cent of the cases. It 

 may be present alone or associated with Fraenkel's organism. In 

 a case of croupous pneumonia the pneumococci are found all 

 through the affected area in the lung, especially in the exudation 

 in the air-cells. They 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. Some- 

 times there occur in pneumonic consolidation areas of suppura- 

 tive 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. 



