226 



BACTERIOLOGY. 



Bacterium pneumonias crouposae (Pntumo- 

 coccus, Friedlander). Cocci ellipsoidal and round, 

 singly, or in pairs (diplococci), rods and thread 

 forms. The cell-membrane thickens, and develops 

 into a gelatinous capsule, which is round if the 

 coccus is single, and ellipsoidal if the cocci occur in 

 pairs or in rod-forms (Fig. 76, Plate I., Fig. 5). 

 Cultivated in a test-tube of nutrient gelatine they 

 grow along the needle track in the form of a round- 

 headed nail (Plate IV., Fig. 2), without liquefaction 



FIG. 76. BACTERIUM PNEUMONIA CROUPOS/E, FROM PLEURAL CAVITY 

 OF A MOUSE, x 1500. A, B. Thread-forms. C, D, E. Short rod-forms. 

 G. Diplococci. H. Cocci. I. Streptococci. [After Zopf.] 



of the gelatine. The cocci when artificially culti- 

 vated have no capsule, but it again appears after 

 their injection into animals. The cocci can also 

 be cultivated on blood serum and on boiled potatoes. 

 They occur in pneumonic exudation.* Inoculation 

 of dogs with a cultivation of the cocci occasionally 

 gave positive results ; but in rabbits no results 



* Friedlander, Fortschr. d. Med. 1883. 



