502 BACTERIOLOGY. 



ized, according to Pfeiffer, by the appearance of two 

 kinds of liquefying colonies, one strikingly like those 

 of the Finkler-Prior organism, the other very similar 

 to those produced by Koch's comma bacillus, though in 

 both cases the liquefaction resulting from the growth of 

 this organism is more energetic than that common to 

 the spirillum of Asiatic cholera. After from twenty- 

 four to thirty hours the medium-size colonies, when 

 examined under a low power of the microscope, show a 

 yellowish-brown, ragged central mass surrounded by a 

 zone of liquefaction that is marked by a border of deli- 

 cate radii. (Fig. 79.) 



Colony of microspira Metchnikovi in gelatin, after thirty hours at 20 to 

 22 C. X about 75 diameters. 



In gelatin stab-cultures the growth has much the 

 same general appearance as that of the cholera spiril- 

 lum, but is exaggerated in degree. The liquefaction 

 is far more rapid, and the characteristic appearance 

 of the growth is lost in from three to four days. 

 (See a, 6, c, d, Fig. 89.) Development and liquefaction 

 along the deeper parts of the needle-track are much 

 more pronounced than is the case with the " comma 

 bacillus." 



Its growth on agar-agar is rapid ; after twenty-four 

 to forty-eight hours a grayish deposit appears, which has 

 a tendency to become yellowish with age. 



On potato at 37 C. its growth is seen as a moist, 

 coffee-colored patch, surrounded by a much paler zone. 



