GROUP OF PYOGENIC COCCI. 
51 
pneumococcus is a small lance-shaped organism ar¬ 
ranged in pairs. These diplococci may form chains 
not unlike the streptococcus in appearance. It is an 
Fig. 6 .—Diplococcus pneumoniae in the heart’s blood of a rabbit. 
X1000. (After Frankel-Pfeiffer.) 
encapsulated diplococcus, the capsule being easily 
stained in smears of the fresh sputum. 
The pneumococcus grows best at body temperature 
on media that contains blood or blood serum. It is 
dissolved in bile, while the streptococcus, with which 
it is easily confused, is not. It is Gram positive. 
