404 BACTERIOLOGY. 



lowish or greenish-yellow color, and marked by very del- 

 icate irregular lines or ridges. After forty-eight hours 

 the plate containing many colonies is entirely liquefied, 

 while that containing only a few shows the presence of 

 round, sharply cut, shallow pits of liquefaction that 

 measure from 2 to 10 mm. in diameter. They are a 

 little denser at the centre than at the periphery, and 

 the dense centre is not sharply circumscribed, but fades 

 off into what has the appearance of a delicate film. 

 (See b, Fig. 82.) As the colonies become older they 

 are sometimes marked by irregular radii extending from 

 periphery to centre like the spokes of a wheel. 



FIG. 82. 



6 



Colonies of Miller's spirillum on gelatin, at 20 to 22 C. X about 57 



diameters. 



a. Colony just beneath the surface of the gelatin. 6. Colony on the surface 

 of the gelatin. 



In stab-cultures in gelatin it rapidly produces lique- 

 faction, both at the surface and along the needle-track, 

 and in most respects gives rise to a condition very like 

 that resulting from the growth of Finkler and Prior's 

 spirillum, though differing from it in certain details. 

 (See a, 6, c, d, Fig. 83.) 



On agar-agar nothing of special interest appears as a 

 result of its development. 



On potato its growth is very like that of the cholera 

 spirillum, viz., it appears at 37 C. as a dry,white patch 



