MILLER'S SPIRILLUM. 349 



Another spirillum that has been likened to that of 

 Koch is the one obtained by Miller from a carious 

 tooth. It has so many characteristics in common with 

 the organism of Finkler and Prior that Miller was 

 inclined to consider them identical. In morphology 

 they are indistinguishable. (See Fig. 70.) It grows 



Fig. 70. 



f 





Spirillum of Miller. From agar culture twenty-four hours old. 



rapidly, and, like the spirillum of Finkler and Prior, 

 causes rapid liquefaction of gelatin with the coincident 

 production of a peculiar aromatic odor. 



The colonies on gelatin plates appear after twenty-four 

 hours as small, transparent pits of liquefaction in the 

 centre of which can be seen a minute white point, the 

 colony itself. Under a low lens the largest of these 

 points are uniformly granular and regularly round, 

 and as a rule are surrounded by a peripheral zone that 

 is a little darker than the central portion of the colony. 

 The circumference is delicately fringed by short, cilia- 

 like prolongations of growth which are not as a rule 

 straight, but are twisted in all directions and can only 

 be detected upon very careful examination. (See a, Fig. 

 71.) When located deep in the gelatin the colonies 

 are round, sharply circumscribed, of a pale-yellowish or 



16 



