SPIRILLA RESEMBLING CHOLERA. 285 



37 C., in this respect, as in its reaction to stains, much 

 resembling the other two. 



Upon gelatin plates the growth of the colonies is much 

 more rapid than that of the cholera spirillum, but slower 

 than that of the Finkler and Prior spirillum. The col- 



FIG. 84. Spirillum Denecke, from an agar-agar culture; x 1000 (Itzerott 

 and Niemann). 



onies appear as small whitish, round points, which soon 

 reach the surface of the gelatin and commence liquefac- 

 tion. By the second day they are about the size of a 

 pin's head, have a yellow color, and occupy the bottom 

 of a conical depression. The appearance is much like 

 that of a plate of cholera spirilla. 



The microscope shows the colonies to be of irregular 

 shape and coarsely granular. The color is yellow, and is 

 pale at the edges, gradually becoming intense toward the 

 centre. The colonies are surrounded at first by distinct 

 lines of circumscription, later by clear zones, which, ac- 

 cording to the illumination, are pale or dark. From this 

 description it will be seen that the colonies differ from 

 those of cholera in the prompt liquefaction of the gelatin, 

 their rapid growth, yellow color, irregular form, and dis- 

 tinct lines of circumscription. 



In gelatin punctures the growth takes place all along 



