472 Pneumonia 



soften and leave the air-cells by the natural passages, and the stage 

 of resolution begins. 



The pneumococci, though present in enormous numbers in the 

 pulmonary lesions, are not confined to them. In practically all 

 cases pneumonia is a blood infection (bacteremia) as well as a pul- 

 monary infection. It is through the blood infection that many of 

 the complications and sequelae of the disease are brought about. 

 Not only are the pneumococci found in this typicallobar form of pneu- 

 monia, but also in the atypical scattered consohdations of the lung 

 known as broncho-pneumonia, catarrhal pneumonia and inspiration 

 pneumonia. Here, however, they are by no means so constant in 

 occurrence. 



The pneumococcus is not infrequently discovered in diseased con- 

 ditions other than croupous pneumonia; thus, Foa, Bordoni-Uffre- 

 duzzi, and others found it in cerebro-spinal meningitis; Frankel, in 

 pleuritis; Weichselbaum, in peritonitis; Banti, in pericarditis; numer- 

 ous observers, in acute abscesses; Gabbi isolated it from a case of 

 suppurative tonsillitis; Axenfeld observed an epidemic of conjunc- 

 tivitis caused by it; Zaufal, Levy, and Schroder and Netter have 

 been able to demonstrate it in the piis of otitis media, and Foulerton 

 and Bonney* isolated it from a case of primary infection of the 

 puerperal uterus. It has also been found in arthritis following pneu- 

 monia, and in primary arthritis without previous pneumonia by 

 Howard, f 



Interesting statistics concerning the relative frequency of pneumo- 

 coccus infections in adults given by Netter { are as follows: 



Pneumonia 6S . 9S 



Broncho-pneumonia 15-85 



Meningitis.. 13.00 



Empyema 8.53 



Otitis media 2 . 44 



Endocarditis 1.22 



Hepatic abscess 1.22 



In 46 consecutive pneumococcus infection of children he found: 



Otitis media 29 ■ 



Broncho-pneumonia 12 



Meningitis 2 



Pneumonia i 



Pleurisy i 



Pericarditis, i 



Susceptibility.- — Not all animals are equally susceptible to the 

 action of the pneumococcus. Mice and rabbits are highly sensitive; 

 dogs, guinea-pigs, cats, and rats are much less susceptible, though 

 they may also succumb to the inoculation of large doses. 



Specificity.- — The etiologic relationship of the pneumococcus to 

 pneumonia is based chiefly upon the frequency of its presence in 



* "Trans. Obstet. Soc. of London," 1903, part n, p. 128. 

 t "Johns Hopkins Hospital Bulletin," Nov., 1903. 

 t"Compte-rendu," 1889. 



