1 86 ACUTE PNEUMONIA. 



definitely contoured capsule which was faintly but dis- 

 tinctly stained. These cocci could be isolated and grown 

 on gelatine, and they assumed in stab cultures on gelatine 

 a very characteristic appearance. On inoculation in mice 

 they produced definite pathogenic effects. Instead of 

 developing pneumonia, however, the animals died of a 

 kind of septicaemia with inflammation of the serous mem- 

 branes. The blood and the exudation in serous cavities 

 contained numerous capsulated diplococci. Though of 

 course this was not proof that the cocci were the cause 

 of the disease in man, Friedlander brought forward the 

 growing tendency to regard pneumonia as an infectious 

 disease, the alleged universal occurrence of his cocci in the 

 lungs of persons dead of the disease, and the pathogenic 

 capacities of these cocci in animals, as indications that an 

 etiological factor had been discovered. Various criticisms 

 of Friedlander's views soon appeared, and there is little 

 doubt that many of the organisms seen by Friedlander 

 were really Fraenkel's pneumococcus to be presently 

 described. 



By many observers it was found that the sputum of 

 healthy men, when injected into animals, sometimes caused 

 death, with the same symptoms as in the case of the injec- 

 tion of Friedlander's coccus ; and in the blood and serous 

 exudations of such animals capsulated cocci were found. 

 A. Fraenkel investigated this subject, and found that the 

 sputum of pneumonic patients was much more fatal and 

 more constant in its effects than that of healthy individuals. 

 The cocci which were found in animals dead of this 

 " sputum septicaemia " as it was called, differed from 

 Friedlander's cocci in not growing at the ordinary tempera- 

 ture. They required to be incubated at higher tempera- 

 tures, and on sloped agar gave a .very thin greyish film of 

 growth. They also differed in shape from Friedlander's 

 cocci, being somewhat oval and pointed at their free 

 extremities. Fraenkel further investigated a few cases of 

 pneumonia, and isolated from them cocci identical in micro- 

 scopic appearances, cultures, and pathogenic effects, with 



