372 BACTERIOLOGY. 



longer, spiral-like filaments. It is usually thicker than 

 Koch's spirillum and is at times much longer, while 

 again it is seen to be shorter. It is usually more dis- 

 tinctly curved than the "comma bacillus." (Fig. 77.) 



It is supplied with a single flagellum at one of its 

 extremities and is, therefore, motile. 



It does not form spores. 



It is aerobic. 



Its growth upon gelatin plates is usually characterized, 

 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-sized colonies, when exam- 

 ined under a low power of the microscope, show a yel- 

 lowish-brown, ragged central mass surrounded by a zone 

 of liquefaction that is marked by a border of delicate 

 radii. (Fig. 78.) 



FIG. 78. 



Colony of vibrio Metchnikmn. 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 spirillum, but 

 is very much 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, 



