PNEUMOBACTERIA IN OTHER CONDITIONS. 21 3 



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. 83). On the surface oi potatoes it forms an abundant 

 moist white layer, in which it is usual to find many small gas- 

 bubbles. 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, lasvolactic acid, succinic 

 acid, along with hydrogen and carbonic acid gas. The amount 

 of acid produced from lactose seems only exceptionally sufficient 

 to cause coagulation of milk. It is said 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. This latter bacillus, however, is 

 non-pathogenic and always acidifies and coagulates milk within 

 24-48 hours, with more or less active formation of gas. 



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 microscopically and 

 culturally, has been found to be present. Friedlander's pneumo- 

 bacillus 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, 

 eg. in an area of acute congestion in a case of croupous pneu- 

 monia, 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 concon;itants. In other cases, 

 especially when the condition is secondary to influenza, gangrene 



