296 Pneumonia 



Pneumonia 65.95 



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 infections of children 

 he found: 



Otitis media 29 



Broncho-pneumonia 12 



Meningitis 2 



Pneumonia 1 



Pleurisy 1 



Pericarditis 1 



Susceptibility. Not all animals are susceptible to the 

 action of the pneumococcus. Guinea-pigs, mice, and rab- 

 bits are highly sensitive, dogs comparatively immune. 



Specificity. The etiologic relationship of the pneumo- 

 coccus to pneumonia is based more upon the frequency 

 with which it is found in that disease than upon its ability 

 to produce a similar affection in the lower animals, and we 

 are still unable to furnish an absolute proof of specificity 

 according to the postulates of Koch. The invariability of 

 its presence in croupous pneumonia is, however, very con- 

 vincing, as Netter * found it 82 times in 82 autopsies upon 

 such cases ; Klemperer, 2 1 times out of 2 1 cases studied by 

 puncturing the lung with a 'hypodermic syringe. Weichsel- 

 baum obtained it in 94 out of 129 cases; Wolf, in 66 out of 

 70 ; and Pierce, in no out of 1 2 1 cases. In about 5 per cent, 

 of the cases it remains localized in the respiratory apparatus ; 

 in 95 per cent, it invades the blood. An interesting paper 

 upon this subject has been written by E. C. Rosenow.f 



The conditions under which it enters the lung to produce 

 pneumonia are not known. It is probable that some 

 systemic depravity is necessary to establish susceptibility, 

 and in support of this view we may point out that pneu- 

 monia is very frequent, and exceptionally severe and fatal, 

 among drunkards, and that it is the most frequent cause of 

 death among the aged. Whether, however, any particular 

 form of vital depression is necessary to predispose to the 

 disease, further study will be required to tell. 



* " Compte-rendu," 1889. 



f'Jour. Infectious Diseases," 1904, i, p. 280. 



