DIPLOCOCCUS LANCEOLATUS. 181 



or lance-shaped extremity, but this shape is seen only in the 

 disease product, and not in culture. Here the organism has 

 more or less of an oval or spherical shape. Each diplococcus 

 in its native state is also surrounded by a capsule (Fig. 7.7). 

 When the germ is cultivated, the capsule is not visible. It is 

 not motile, has no flagella, and does not sporulate. It stains 

 with the anilin dyes and by Gram's method, differing in that 

 respect from both the gonococcus and the rneningococcus. It 

 is a facultative anaerobe. 



Although the pneumococcus will grow at a temperature as 

 low as 71 F., its temperature optimum is more nearly the 



FIG. 77. 



Diplococcus of pneumonia, with surrounding capsule. (Park.) 



temperature of the body. A ten minute exposure to a tem- 

 perature of 52 C. kills the germ. The conditions in culture 

 must be absolutely favorable to the development of the germ, 

 as it possesses but little vitality outside of the body. 



The pneumococcus was observed first by Sternberg in the 

 saliva of healthy persons. For culture purposes it is obtained 

 best directly from pneumonic sputum. A rabbit is inoculated 

 with the sputum, and after a few hours the germ is obtained 

 from the blood of the animal. Kitasato advises washing the 

 sputum of the pneumonic patient in sterile water until it has 

 been freed from all contaminating organisms, then separating 

 the mass and transplanting its central portion to the culture- 

 medium. 



