18 BIOLOGY OF PNEUMOCOCCUS 



in a percentage of cases sufficiently high to promise diagnostic 

 value, and gave clear and detailed descriptions of their isolation, 

 cultivation, and animal pathogenicity. He added the gums, tonsils, 

 accessory sinuses, cerebrospinal fluid, and joints as sites of pneu- 

 mococcal infection. The organism differed, as in Fraenkel's experi- 

 ence, from Friedlander's in that it failed to grow on gelatin, while 

 the author emphatically differed from Fraenkel in the belief that 

 this coccus was the sole cause of pneumonia. 



Weichselbaum (1886) 1498 " 1500 separated pneumonic affections 

 into lobar, croupous, lobular, and hypostatic pneumonias, fixed on 

 Pneumococcus the guilt of causing the lobar type, and on strepto- 

 cocci, staphylococci, and a bacillus (Bacillus pneumoniae — prob- 

 ably the Friedlander bacillus) that of producing the other types. 

 He presented new data concerning the morphology and growth 

 characters of Pneumococcus ; from the infected lung tracked the 

 organism through the lymphatics to the cerebral ventricles ; and 

 suggested the blood stream as a further avenue of its spread. To 

 the organism Weichselbaum gave the name Diplococcus pneu- 

 moniae. In the next year (1887), Weichselbaum repeated Stern- 

 berg's work and, in addition, by the subcutaneous injection of 

 dried spleens from animals succumbing to the diplococcal infec- 

 tion, and of post-pneumonic pleural exudate containing attenuated 

 pneumococci, immunized mice and rabbits. He, like Fraenkel, called 

 the organism Pneumococcus. 



In the same year, confirmation of the diversity of organisms in- 

 volved in pneumonia came from Wolf, 1529 while Meyer 895 offered 

 further proof of the presence of pneumococci in the lungs, heart, 

 and cerebrospinal exudates in infections secondary to pneumonia. 

 Netter, 965 finding these same cocci in the nasal fossae, sinuses, and 

 tympanic cavity, then made the original observation that a local 

 process, such as pneumococcal meningitis, could arise without a 

 contributing lung infection. 



Sternberg, not yet entirely convinced that the lanceolate diplo- 

 coccus was the true cause of pneumonia, but hoping for a better 



