THE PNEUMOCOCCUS 483 



quite distinct, and that the former is the etiological agent of acute 

 croupous pneumonia ; it is frequently known as Franker s pneumo- 

 coccus. 



From pleuro -pneumonia of cattle, Nocard and Koux succeeded 

 in cultivating in broth in collodion sacs in the peritoneal cavity of 

 rabbits an organism just visible as minute granules with a magni- 

 fication of 2,000 diameters (B. [Hemophilus] bronchisepticus). 

 Bordet 1 states that it may be grown on the medium employed by 

 him for the cultivation of the B. pertussis (p. 499), and then 

 appears as fine, straight, curved, undulating, or even spirillar 

 filaments not unlike spirochsetes. 



The Streptococcus [DiplococcusJ pneumonias 



Morphology. The Streptococcus pneumonice occurs in 

 the sputum and tissues as an oval or lance-shaped coccus 

 united in pairs, occasionally in chains of three or four 

 elements, which are then often almost spherical, and is 

 generally surrounded by a well-marked capsule (Plate 

 XVI, b). In order to isolate the organism several tubes of 

 agar, blood-agar or Fleming's medium (p. 498) may be 

 inoculated in succession with the same loopful of rusty 

 sputum and incubated for forty-eight hours ; in some a 

 pure culture may be obtained. A more certain method is 

 to inject a drop or two of the rusty sputum into the 

 peritoneal cavity of a mouse or young rabbit. The 

 animal will die in from twenty -four to thirty-six hours, 

 and the organism will be found in considerable numbers 

 in the lung and blood (Plate XVII, a), from which cultures 

 may be obtained. It is non-motile, stains with the 

 ordinary anilin dyes and by Gram's method. 



Cultural characters. The 8. pneumonice is aerobic and 

 facultatively anaerobic. On agar at 37 C. it forms 

 minute, transparent, almost invisible colonies like droplets 

 of fluid ; on serum the growth has much the same cha- 

 racters, but is somewhat more abundant. It hardly 



1 Ann. de Vlnst. Pasteur, xxiv, 1910, p. 161. 



312 



