452 Pneumonia 



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. 



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 pus 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 65.95 



Broncho-pneumonia 15 . 85 



Meningitis 13 . oo 



Empyema 8 . 53 



Otitis media 2 . 44 



Endocarditis 1.22 



Hepatic abscess 1.22 



In 46 consecutive pneumococcus infections 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 

 croupous pneumonia. Netter found it 82 times in 82 autopsies 

 upon such cases; Klemperer, 21 times out of 21 cases studied by 

 puncturing the lung with a hypodermic syringe. Weichselbaum ob- 

 tained it in 94 out of 129 cases; Wolf, in 66 out of 70; and Pierce, 

 in no out of 121 cases. In about 5 per cent, of the cases it remains 

 localized in the respiratory apparatus; in 95 per cent., it invades the 



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

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

 t" Compte-rendu," 1889. 

 "Compte-rendu," i88q. 



