THE PNEUMOCOOCUS 407 



they are quite distinct, and that the former is the etiological agent 

 of acute croupous pneumonia. 



The majority (95 per cent.) of cases of acute croupous pneumonia 

 are caused by the Streptococcus pneumonice, and Friedlander's 

 organism, now termed Friedlander's pneumo-bacillus, or B. pneu- 

 monice, is of etiological significance in only a small minority, if at 

 all. The latter is, however, associated with certain pathological 

 processes which will be referred to below. 



From pleuro-pneumonia of cattle, Nocard and Roux succeeded 

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

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

 tion of 2000 diameters. Bordet x states that it may be grown on 

 the medium employed by him for the cultivation of the B. pertussis 

 (p. 417), and then appears as fine, straight, curved, undulating, or 

 even spirillar filaments not unlike spirochaetes. 



The Streptococcus (Diplococcus) pneumoniae 



Synonyms, Frankel's pneumococcus, Micrococcus Pasteuri (Stern- 

 berg), Micrococcus lanceolatus (Talamon), Micrococcus pyogenes 

 tenuis (Rosenbach). 



Morphology. The Streptococcus pneumonice in the sputum 

 and tissues occurs as an oval or lance- shaped coccus united 

 in pairs, occasionally in chains of three or four elements, 

 and then often almost spherical, and is generally surrounded 

 by a well-marked capsule (Plate XVI. a). In order to 

 isolate the organism several tubes of glycerin agar, serum 

 or serum- agar may be inoculated with 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, from which cultures may be obtained. It is non- 

 motile, stains with the ordinary anilin dyes and by Gram's 

 method. 



1 Ann. de VInst. Pasteur, xxiv, 1910. March. 



