242 BAGTERIOLOGT. 



should occur, it is iu all probability due to a disappear- 

 ance of virulence from the organism. 



This organism was discovered by Sternberg in 1880. 

 It was subsequently described by A. Frankel as the 

 etiological factor in the production of acute fibrinous 

 pneumonia. 



It is not uncommonly present in the saliva of healthy 

 individuals, having been found by Sternberg in the oral 

 cavity of about 20 per cent, of healthy persons examined 

 by him. It is constantly to be detected in the rusty 

 sputum of patients suffering from acute fibrinous pneu- 

 monia. Its presence has been detected in the middle 

 ear, in the pericardial sac, in the pleura, in the serous 

 ca,vities of the brain, and indeed it may penetrate from 

 its primary seat in the mouth to almost any of the 

 more distant organs. 



The organism is commonly found as a diplococcus, 

 though here and there short chains of four to six indi- 

 viduals joined together may be detected. (Fig. 51, 

 page 239.) The morphology of the individual cells is 

 more or less oval, or, more strictly speaking, lancet- 

 shaped, for at one end it is commonly pointed. When 

 joined in pairs the junction is always between the 

 broad ends of the ovals, never between the pointed 

 extremities. 



As already stated, in preparations directly from the 

 sputum or from the blood of animals, a delicate cap- 

 sule may frequently be seen surrounding them. Though 

 fairly constant in preparations directly from the blood 

 of animals and from the sputum or lungs of pneumonic 

 patients, the capsule is but rarely observed in artificial 

 cultures. Occasionally in cultures on blood-serum, in 

 milk, and on agar-agar they can, according to some 



