526 APPLICATION OF METHODS OF BACTERIOLOGY 



On plates 2 and 3, where the colonies are more widely 

 separated, they can be seen after twenty-four to thirty 

 hours as small, round or oval, white or cream-white points, 

 and when located superficially a narrow transparent zone 

 of liquefaction can be detected around them. As growth 

 continues this liquefaction extends downward rather than 

 laterally, and the colony ultimately assumes the appearance 

 of a dense, white mass lying at the bottom of a sharply-cut 



Fig. 90 



Development phases of colonies of mierospira comma at 20° to 22° C. on 

 gelatin. X about 75 diameters, u, after sixteen to eighteen hours; b, after 

 twenty-four to twenty-six hours; c, after thirty-eight to forty hours; d, after 

 forty-eight to fifty hours; e, after sixty-four to seventy hours. 



pit or funnel containing transparent fluid. This liquefaction 

 is never very widespread nor rapid, and rarely extends 

 more than one millimeter beyond the colony proper. On 

 plates containing few colonies there is little or no tendency 

 for them to become confluent, and they rarely exceed 2 

 to 3 mm. in diameter. 



When examined under a low magnifying lens the very 

 young colonies (sixteen to eighteen hours old) appear as 

 pale, translucent, granular globules of a very delicate 



