Cultivation 



509 



Morphology. Though usually dis- 

 tinctly bacillary in form, the organism 

 is of variable length and when paired 

 sometimes bears a close resemblance 

 to the pneumococcus of Frankel and 

 Weichselbaum It measures 0.5 to 

 1.5 ^ in breadth and 0.6 to 0.5 [A in 

 length. It frequently occurs in 

 chains of four or more elements and 

 occasionally appears elongated. It is 

 these variations in form that have 

 led to the description of the organism 

 by different writers as a coccus, a 

 bacterium, and a bacillus. It is com- 

 monly surrounded by a distinct trans- 

 parent capsule, hence its name " cap- 

 sule bacillus" and Bacillus capsulatus 

 mucosus. The organism is non- 

 motile, has no spores, and no flagella. 

 It stains well with the ordinary anilin 

 dyes, but does not retain the color 

 when stained by Gram's method. 



Cultivation. Colonies. If pneu- 

 monic exudate be mixed with gelatin 

 and poured upon plates, small white 

 spheric colonies appear at the end of 

 twenty-four hours, and spread out 

 upon the surface of the gelatin to 

 form whitish masses of a considerable 

 size. Under the microscope these 

 colonies appear irregular in outline 

 and somewhat granular. 



Bouillon. There is nothing char- 

 acteristic about the bouillon cultures 

 of Friedlander's bacillus. The me- 

 dium is diffusely clouded. A pellicle 

 usually forms on the surface and a 

 viscid sediment soon accumulates. 



Gelatin Puncture. When a colony 

 is transferred to a gelatin puncture 

 culture, a luxuriant growth occurs. 

 Upon the surface a somewhat ele- 

 vated, rounded white mass is formed, 



Fig. 165. Friedlan- 

 der's pneumobacillus ; 

 gelatin stab culture, 

 showing the typical 

 nail-head appearance 

 and the formation of 

 gas bubbles, not always 

 present (Curtis). 



