SUPPURA TION. 255 



cus longus, sometimes forms chains of more than one 

 hundred members. 



The organism stains well with ordinary aqueous solu- 

 tions of the anilin dyes, and also by Gram's method. Like 

 the coccus already described, it is not motile and does not 

 seem to form spores, though sometimes a large individual 

 — much larger than the others in its chain — may be ob- 

 served, and may suggest the thought of arthro-sporulation. 



Upon gelatin plates very small colonies of translucent 

 appearance are observed. 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, and to have numerous 

 irregularities around the edges, due to projecting chains 

 of the cocci. No liquefaction occurs. 



In gelatin puncture-cultures no liquefaction is observed. 

 The minute spherical colonies grow along the whole 

 needle-track and form a slightly opaque granular line. 



Upon agar-agar an exceedingly delicate transparent 

 growth develops slowly along the line of inoculation. 

 It consists of almost transparent, colorless small colonies 

 which do not become confluent. 



The growth upon blood-serum much resembles that 

 upon agar-agar. The streptococcus does not seem to 

 grow upon potato, or produces an invisible growth only. 



In bouillon the cocci develop rather slowly, seeming 

 to prefer a neutral or feebly acid reaction. The culture- 

 medium remains clear, while numerous small flocculi are 

 suspended in it. When the flocculi-formation is very 

 distinct the name Streptococcus conglotneratus is used 

 to describe the organism. These masses sometimes ad- 

 here to the sides of the tube; sometimes they form a sedi- 

 ment. Rarely, there is general clouding of the medium 

 {Streptococcus diffusus). 



In mixtures of bouillon and blood-serum or ascitic 

 fluid the streptococcus grows much better, especially at 

 incubation temperatures, and in such mixtures the lux- 

 uriant development causes the liquid to appear clouded. 



