CULTIVATION OF PNEUMOBACILLUS 



203 



differs generally in its more vigorous growth, in producing a 



uniform cloud in bouillon, in slowly liquefying gelatin, and in 



growing on potato. 



The Cultivation of Friedlander's Pneumobacillus. This 



organism, when present in sputum or in a pneumonic lung, can 

 be readily separated by making ordinary 

 gelatin plate cultures, or a series of successive 

 strokes on agar tubes. The surface colonies 

 always appear as white discs which become 

 raised from the surface so as to appear like 

 little knobs of ivory. From these, pure 

 cultures can be readily obtained. The ap- 

 pearance of a stab culture in gelatin growth 

 is very characteristic. At the site of the 

 puncture, there is on the surface a white 

 growth heaped up, it may be fully one-eighth 

 of an inch above the level of the gelatin ; 

 along the needle track there is a white 



FIG. 69. Stab culture 

 of Friedlander's 

 pneumobacillus in 

 peptone gelatin, 

 showing the riail- 

 like appearance ; 

 ten days' growth. 

 Natural size. 



FIG. 70. Friedlander's pneumobacillus, 1 

 from a young culture on agar, showing 

 some rod-shaped forms. 

 Stained with thioniu-blue. x 1000. 



granular appearance, so that the whole resembles a white round- 

 headed nail driven into the gelatin (Fig. 69). Hence the name 



1 The apparent size of this organism, on account of the nature of its sheath, 

 varies much according to the stain used. If stained with a strong stain, e.g. 

 carbol-fuchsin, its thickness appears nearly twice as great as is shown in the 



