130 



BACTERIA 



with blood. The streptococcus causes a haemolysis of the corpuscles, 

 while the pneumococcus does not and the colonies are greenish. 



Oxygen Relations. It is a facultative aerobe. 



Grows rapidly, but never luxuriantly at 37.5 C.; at 22 C. much 

 more slowly, often not at all. Grows better in the presence of 

 serum or hemoglobin. 



FIG. 39. Diplococcus pneumonias, from the heart's blood of a rabbit. Xiooo 

 (Frankel and Pfeiffer.) 



Vital Resistance. Easily killed at a temperature of 52 C., ex- 

 posed for ten minutes. Direct sunlight also kills it in twelve hours. 

 While it quickly dies on ordinary culture media, it may live in dried 

 sputum or pus exposed to diffuse sunlight and desiccation, for four 

 months. 



Cultures. On gelatine plate it produces very minute colonies 



