VIBRIO PROTEUS. 475 



forty-eight hours on gelatin they usually range from 

 one to three millimetres (some even larger) in diameter, 

 and appear as sharply cut, saucer-shaped pits of lique- 

 faction, in the most dependent portion of which lies 

 a dense, irregular mass, the colony proper. Under ^ 

 low magnifying power they present at this stage an ap- 

 pearance similar to that shown in Fig. 80, 6, the central 

 dense mass representing the colony, and the irregular, 



Fig. 80. 



'iX^\ 



. ^ 



Colonies of the Finkler-Prior bacillus oa gelatin X about 75 diameters 



a,. After twenty-two hours at 20° to 22° C 6 After forty eight hours at 



20° to 22° C. 



ragged lines surrounding it being shreds that have be- 

 come torn away as it sank into the liquid caused by its 

 growth. The zone surrounding it, extending to the 

 periphery, is somewhat cloudy, and is simply liquefied 

 gelatin. There is a marked tendency for the liquefac- 

 tion to spread laterally and for the colonies to run 

 together, so that, even on plates containing few colonies, 

 in sixty to seventy-two hours at from 20° to 22° C, the 

 entire gelatin is usually converted into a yellowish- 

 white fluid. Under these conditions growth is ac- 

 companied by a marked aromatic odor, impossible to 



