CHAPTER XVII 

 THE PNEUMOCOCCUS 



The pneumococcus, also called the diplococcus 

 ianceolatus, 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 



*' « — 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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