206 ACUTE PNEUMONIA. 



views soon appeared, and there is little doubt that many of the organ- 

 isms 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 injection of Friedlander's coccus ; and 

 in the blood and serous exudations of such animals capsulated diplo- 

 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 several respects to be 

 presently studied. Fraenkel further investigated a few cases of pneu- 

 monia, and isolated from them cocci identical in microscopic appear- 

 ances, cultures, and pathogenic effects, with those isolated in sputum 

 septicaemia. The most extensive investigations on the whole question 

 were those of Weichselbaum, published in 1886. This author 

 examined 1 29 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 ) Diplococciis pneumonia. 

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

 appearance and growth characters to Fraenkel's coccus. (2) Strepto- 

 coccus pneumonia. This was less common than the last, was rounder, 

 and formed longer and more twisted chains, but on the whole pre- 

 sented similar characters. 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 must be classed among the 

 bacilli. Weichselbaum, however, was of opinion that it was identical 

 with Friedlander's pneumococcus. 



Of these organisms the diplococcus pneumonioe was by far the most 

 frequent, being observed in 94 cases of the 1 29 examined, and isolated 

 by cultures in 54. It also occurred in all forms of pneumonia. Next 

 in frequency was the streptococcus pneumonia?, and lastly the bacillus 

 pneumonise. Inoculation experiments were also performed by Weichsel- 

 baum with each of the three characteristic cocci he isolated. The 

 diplococcus pneumonise and the streptococcus pneumonise both gave 

 pathogenic effects of a similar kind in certain animals. 



The general result of these earlier observations was to 

 establish the occurrence in connection with pneumonia 

 of two species of organisms, each having its distinctive 

 characters, viz. : 



i. Fraenkets pneumococcus, which is recognised to be 

 identical with the coccus of "sputum septicaemia," with 



