MICROCOCOUS LANCEOLATUS. 511 



medium for these parasites in the body, brought about 

 by an abnormal condition of the mucous membranes 

 from exposure to cold, or a reduction of the vital re- 

 sisting power of the tissue cells in any of the internal 

 organs, caused by disease, traumatism, excesses of vari- 

 ous kinds, etc. , to readily comprehend how an individual 

 may become infected with pneumonia, either primarily 

 affecting the lungs and secondarily other organs in the 

 body, or primarily attacking the middle ear, the pericar- 

 dial sac, the pleura, the serous cavities of the brain, etc. 

 From statistics collected by Netter the following per- 

 centages of diseases were caused by the ' ' diplococcus 

 pneumonias 7 ' : 



Pneumonia 'r- . . . 65.9 per cent, in adults. 



Bronchopneurnonia . . 15.8 ' 



Meningitis. . . .13.0 ' 



Empyema . . . . 8.5 ' " 



Otitis media . . . 2.4 ' " 



Endocarditis . . . 1.2 ' " 



In 46 consecutive pneumococcus infections in chil- 

 dren there were : 



Otitis media . * ' . . . 29 cases. 



Bronchopneumonia . . . . 12 " 



Meningitis . . . . . . 2 ll 



Pneumonia . . . ... 1 " 



Pleurisy . . . . 1 " 



Pericarditis . . . ... 1 " 



Varieties of the Micrococcus Lanceolatus. The ubi- 

 quity of this organism and the irregularity of its 

 behavior under varying conditions have opened a wide 

 field of discussion among bacteriologists. As com- 

 monly found, for instance, in the saliva of different 

 healthy individuals, and even in that of the same in- 

 dividual at different times, it often varies in virulence; 



