252 MANUAL or BACTERIOLOGY. 



air-vesicles, which in the early part of the disease contains red 

 blood-cells, imparting the rusty color to the sputum. The 

 principal element in the exudate is fibrin. The formation of 

 fibrin produces the Hver-like consolidation or "hepatization." 

 The diplococci can readily be demonstrated by the Gram 

 method in sections of pneumonic lung, which are best stained 

 by carmine and gentian-violet. 



The Micrococcus lanceolatus can be detected in large num- 

 bers, sometimes almost unmixed with other bacteria, in the 

 rusty sputum of lobar pneumonia, often showing the peculiar 

 unstained capsule. On account of its liability to be mixed 

 with other forms of bacteria its presence in the sputum of 

 cases suspected of being pneumonia is not of very great value 

 in differential diagnosis, especially since it is so commonly 

 present in the normal mouth. In a suspicious case its appear- 

 ance in sputum in nearly pure culture may be significant. 



Cultures from the blood of cases of pneumonia, where a 

 large amount of blood is taken, have shown the presence of 

 the pneumococcus in a considerable proportion of the cases, 

 especially when severe or fatal. 



The Micrococcus lanceolatus is often also the cause of 

 bronchopneumonia and of meningitis. It produces inflam- 

 mations in other situations as well, the most important being 

 pleuritis, pericarditis, endocarditis and arthritis. The Micro- 

 coccus lanceolatus may produce pseudomembranous inflam- 

 mation* and also ordinary suppuration, although not very 

 commonly. 



G. and F. Klemperer claim to have obtained toxins from 

 cultures of the pneumococcus, and to have established im- 

 munity in animals with the development in the blood of anti- 

 toxic substances. Similar attempts have been made by Wash- 



* Cary and Lyon. American Journal Medical Sciences. Vol. CXXII. 

 1901. 



