I 



PATHOGENIC BACTERIA. 24! 



ring in bone, but which does not present the ordinary 

 picture of pus-formation owing to the hard and unyielding 

 character of the tissue. Other conditions of very great 

 importance are meningitis, pericarditis, pleuritis, pneumo- 

 nia (croupous and broncho-), peritonitis and endocarditis. 

 It will be observed that these affections are, for the most 

 part, inflammations of the serous membranes. Such in- 

 flammations, when they are produced by pyogenic bac- 

 teria, are likely to be of great severity, accompanied by 

 the formation of fibrinous exudates ; pus-formation may or 

 may not be present. We find that the cause at times is 

 the staphylococcus pyogenes aureus; this is often the case 

 in malignant endocarditis. Generally speaking, in such in- 

 flammations the streptococcus pyogenes, the staphylococcus 

 pyogenes aureus, and the pneumococcus occur most com- 

 monly, although they are by no means the only organisms 

 found. Many cases of peritonitis show the presence of B. 

 coli communis, either in combination with other bacteria, 

 or alone. 1 This is explained by the proximity of the intes- 

 tine, and especially by the frequent occurrence of peritonitis 

 after perforation of the intestine. 



In inflammations of mucous membranes the common 

 pyogenic organisms play the most important though not an 

 exclusive part. In acute bronchitis, pneumococci and strep- 

 tococci were found by Ritchie to be the commonest causes. 



In inflammations of the middle ear the principal causes are 

 the pneumococcus, the streptococcus, and the staphylococcus 

 aureus and albus. 3 



In 25 cases of acute cystitis in women Brown 4 found 

 B. coli communis, 15 times; S. pyogenes albus, 5 times; S. 



1 Flexner, " Etiology, etc., of Peritonitis," Philadelphia Medical Jour- 

 nal, November 12, 1898. 



2 Ritchie, Journal Pathology and Bacteriology, Vol. VII., December, 

 1900. 



3 Hasslauer, Ccntralblatt f. Baktcriologic, XXXII., Ref., 1902, p. 174. 

 Compare Ibidem, pp. 240 and 246. 



4 Johns Hopkins Hospital Reports, Vol. X., 1902. 



