CHAPTER XVI 



PNEUMOCOCCUS, MENINGOCOCCUS, GONOCOCCUS 



THE term pneumonia is used to designate a variety of pathogenic 

 conditions of the lung or the parts which compose it. Of these 

 the two forms most generally met with are : lobar pneumonia 

 (acute croupous), an inflammatory process accompanied by 

 abundant fibrinous exudate rapidly involving the entire tissue of 



a lobe or a large portion of it, 

 and lobular pneumonia (bron- 

 cho-pneumonia) , a catarrhal 

 inflammatory type spreading 

 from the capillary bronchi to 

 the air vesicles and often result- 

 ing in consolidation of patches 

 of the lung tissue. 



A number of microorganisms 

 may give rise to pneumonia; 

 such for example as B. mucosus 

 capsulatus, B. diphtherise, B. 

 pestis, B. typhosus, strepto- 

 cocci, and staphylococci. For the most part, however, these 

 organisms produce the lobular type. 



In lobar pneumonia about 95 per cent of all the cases are caused 

 by a lancet-shaped micrococcus upon which various names have 

 been bestowed, such as pneumococcus, diplococcus pneumonice, 

 micrococcus lanceolatus, or after its discoverer, Frankel's pneumo- 

 coccus. (Fig. 25.) 



The pneumococcus was observed almost simultaneously by 

 Pasteur and Sternberg in 1880 in the blood of rabbits inoculated 



164 



Fio. 25. Pneumococci. 



