CHARACTERS OF BACTERIA OF PNEUMONIA. 207 



1880, and by Pasteur, in December of the same year. A. Fraenkel 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, 11 as it was called, differed from 

 Friedlander's cocci in several respects to be presently studied. Fraenkel fur- 

 ther investigated a few cases of pneumonia, and isolated from them cocci 

 identical in miscroscopic appearances, cultures, and pathogenic effects, with 

 those isolated in sputum septicaemia. The most extensive investigations on 

 the whole question were those of Weicliselbaum, published in 1886. This 

 author examined 129 cases of the disease, and included in his survey not only 

 acute croupous pneumonia, but lobular and septic pneumonias. From them 

 he isolated four groups of organisms, (i) Diplococcus pneumonia. This he 

 described as an oval or lancet-formed coccus, corresponding in appearance 

 and growth characters to Fraenkel's coccus. (2) Streptococcus pneiimonice . 

 This on the whole presented similar characters to the last but it was more 

 vigorous in its growth, and could grow below 20 C., though it preferred a 

 temperature of 37 C. (3) Staphylococcus pyogenes aureus. (4) Bacillus 

 pneumonia. This was a short, rod-shaped organism, which in Weichselbaum's 

 opinion was identical with Friedlander's pneumococcus. Of these organisms 

 the diplococcus pneumoniae was by far the most frequent. It also occurred 

 in all forms of pneumonia. Next in frequency was the streptococcus pneu- 

 moniae, and lastly the bacillus pneumoniae. Inoculation experiments were also 

 performed by Weichselbaum with each of the three characteristic cocci he 

 isolated. The diplococcus pneumoniae and the streptococcus pneumoniae both 

 gave pathogenic effects of a similar kind in certain animals. 



The general result of these earlier observations was to estab- 

 lish the occurrence in connection with pneumonia of two species 

 of organisms, each having its distinctive characters, viz. : 



1. Fraenkel's pneumococcus, which is recognised to be identical 

 with the coccus of " sputum septicaemia," with Weichselbaum's 

 diplococcus pneumoniae, and probably also with his streptococcus 

 pneumoniae. 



2. Friedlander's pneumococcus (now known as Friedlander's 

 pneumobacillus), which is almost certainly the same as the 

 bacillus pneumoniae of Weichselbaum. 



We shall use the terms " Fraenkel's pneumococcus " and 

 " Friedlander's pneumobacillus," as these are now usually applied 

 to the two organisms. 



Microscopic Characters of the Bacteria of Pneumonia. - 

 Methods. The organisms present in acute pneumonia can best 

 be examined in film preparations made from pneumonic lung 

 (preferably from a part in a stage of acute congestion or early 

 hepatisation), or from the gelatinous parts of pneumonic sputum, 



