3IO 



Suppuration 



and Streptococcus brevis (chains of from four to ten), have been 

 described by v. Lingelsheim,* but do not hold as separate species. 



The streptococcus is not motile and does not form spores. 



Staining. — The organisms stain well with ordinary aqueous 

 solutions of anilin dyes and by Gram's method. 



Isolation. — The streptococcus can be isolated from pus contain- 

 ing it by plating or by the inoculation of a mouse or rabbit, from 

 whose blood it may easily be secured after death. 



Cultivation. — The organism grows at both the room temperature 

 and that of incubation, its best and most rapid development being 

 at about 37°C. 



Colonies. — Upon gelatin plates very small, colorless, translucent 

 colonies appear in from twenty-four to forty-eight hours. When 

 superficial, they spread out to form flat disks about 0.5 mm. in 

 diameter. The microscope shows them to be irregular and granular, 

 to have a slightly yellowish color by transmitted light, and to have 

 a frayed-out appearance around the edges, due to projecting chains 

 of the cocci. No liquefaction of the gelatin occurs. 



Gelatin Punctures. — In gelatin puncture cultures no liquefaction 

 is observed. The minute spheric colonies grow along the whole 

 length of the puncture and form a slightly opaque granular line. 



Fig. no. — Streptococcus colonies on serum agar (From Hiss and Zinsser, 

 "Text-Book of Bacteriology," D. Appleton & Co., Publishers). 



Agar-agar. — Upon agar-agar a delicate transparent growth de- 

 velops slowly along the Hne of inoculation. It consists of small, 

 colorless, or slightly grayish transparent colonies which do not readily 

 coalesce. 



Blood-serum.- — The growth upon blood-serum resembles that upon 

 agar-agar. The colonies are small, white, discrete, and do not afiect 

 the medium. 



Potato. — The streptococcus does not seem to grow well upon 

 potato, the colonies being invisible. 



Bouillon. — In bouillon the cocci develop slowly, seeming to prefer 

 a neutral or feebly alkaline reaction. The medium remains clear, 



* "Zeitschrift fur Hygiene," 1891, Bd. x, p. 331; 1892, xii, p. 308. 



