346 PATHOGENIC BACTERIA. 



position to occur in pairs, and not infrequently forms 

 chains of five or six members, so that some have been 

 disposed to look upon it as a streptococcus (Gamaleia). 

 In the fibrinous exudate from croupous pneumonia, in 

 the rusty sputum, and in the blood of rabbits and mice 

 containing them the organisms are arranged in pairs, 

 exhibit a distinct lanceolate shape, the pointed ends 

 generally approximated, and are usually surrounded by 

 a distinct halo or capsule of clear, colorless, homogeneous 

 material, thought by some to be a swollen cell-wall, by 



FlG. 98. Diplococcus pneumonise, from the heart's blood of a rabbit ; x 1000 

 (Frank el and Pfeiffer). 



others a mucus-like secretion given off by the cells. When 

 grown ordinarily in culture-media, and especially upon 

 solid media, the capsules are absent. 



The organism is without motility, has no spores, and 

 does not seem to be able to resist any unfavorable con- 

 ditions when grown artificially. It stains well with the 

 ordinary solutions of the anilin dyes, and gives most 



