CHAPTER XVII 

 THE PNEUMOCOCCUS 



THE pneumococcus, also called the diplococcus 

 lanceolatus, was discovered by Frankel. As its name 

 implies, the organism occurs usually in lance-shaped 

 twos. It is not decolorized when stained according to 



Blood corpuscle 





Pneumococci-*:** ' *- Blood corpuscle 



I 



V '! ^Pneumococci 



" : 



Fig. 33. Capsulated pneumococci in blood from the heart of a rabbit; 

 carbol-fuchsin, partly decolorized; XlOOO (McFarland). 



Gram's method, and when occurring in sputum or blood 

 is usually surrounded by a thick gelatinous capsule. 

 The pneumococcus is non-motile and does not produce 

 spores. It grows on ordinary media, but prefers those 

 to which a little blood or blood-serum has been added. 

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