170 BIOLOGY OF PNEUMOCOCCUS 



in character all the way from typical Diplococcus lanceolatus to 

 Streptococcus pyogenes. The authors stated that the relation of 

 pneumococci to streptococci was clearly evident, and that the ori- 

 gin of these bacterial species was a single, probably saprophytic, 

 streptococcal form. 



There the matter rested until 1907, when Buerger and Rytten- 

 berg 169 described an organism isolated from a case of puerperal 

 pneumococcemia which, although originally failing to ferment 

 inulin and exhibiting streptococcal characters, developed into a 

 typical pneumococcus after animal passage. The observation led 

 the authors to study a number of cultures isolated from human 

 exudates and blood, and with these strains they observed charac- 

 ters typical of streptococci which, however, gave way to pneumo- 

 coccal characters after propagation in mice. Buerger and Rytten- 

 berg concluded : 



The tendency of pneumococci of the streptococcus cultural type as 

 well as those which have been converted to the normal variety, seems to 

 be toward a gradual degeneration which manifests itself in the assump- 

 tion of permanent streptococcic features. Such organisms can then no 

 longer be differentiated from streptococci. 



In 1909, Rosenow 1162 made the statement that strains of Strep- 

 tococcus viridans isolated chiefly from the blood in cases of sub- 

 acute endocarditis and obtained also from the throat and other 

 sources might by animal passage take on the properties of typi- 

 cal pneumococci, and hence designated them as "modified pneumo- 

 cocci." Rosenow also claimed that during a study of autolysis of 

 pneumococci in salt solution and of the effect of sodium oleate and 

 bile on virulent pneumococci he had observed transformation of 

 the strains into hemolytic streptococci. The statement appears to 

 be conservative when compared to Rosenow's 1170 description in 

 1914 of the various transmutations accomplished within the Strep- 

 tococcus-Pneumococcus group. He told of converting by cultural 

 methods twenty-one strains originally isolated as hemolytic strep- 



