262 Wound Infection; Suppuration 



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. 



Agar-agar. Upon agar-agar an exceedingly delicate 

 transparent growth develops slowly along the line of inocu- 

 lation. 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, dis- 

 crete, and do not affect 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 acid reaction. The medium 

 remains clear, while numerous small flocculi are suspended 

 in it, sometimes adhering to the sides of the tube, sometimes 

 forming a sediment. When the flocculi-formation is distinct, 

 the name Streptococcus conglomerate (Kurth) is sometimes 

 given to the organism ; when the medium is diffusely clouded, 

 it is called Streptococcus diffusus. 



In mixtures of bouillon and blood-serum or ascitic fluid 

 the streptococcus grows more luxuriantly, especially at in- 

 cubation temperatures, distinctly clouding the liquid. 



Milk. The organism seems to grow well in milk, which is 

 coagulated and digested. 



Reaction. The streptococcus is not very sensitive to 

 acids, and can be grown quite well in media with a slightly 

 acid reaction. 



Vital Resistance. Sternberg found that the streptococci 

 succumb at temperatures of 52-54 C. if maintained for ten 

 minutes. Their vitality in culture is slight, and unless 

 frequently transplanted they die. Bouillon cultures usually 

 die in from five to ten days. On solid media they seem to 

 retain their vegetative and pathogenic powers much longer, 

 especially if kept cool and cultivated beneath the surface 

 of the medium in a deep puncture. They resist drying 

 well. The growth in artificial media is accompanied by the 

 production of an acid which probably acts destructively 

 upon the bacteria themselves and first inhibits further 

 growth, then destroys them. 



