154 



ESSENTIALS OF BACTERIOLOGY. 



is not found in unopened buboes, though often contaminating 

 the ulcerated ones. 



Bacillus Icteroides. 



(Sanarelli, 1897.] 

 FIG. 88. 



Bacillus icteroides (Sanarelli). 



Considered the cause of yellow fever by Sanarelli, but Stern- 

 berg and Novy regard this as not determined. It is not 

 identical, as was once supposed, with the Bacillus X of Stern- 

 berg, which is a variety of the Bacillus Coli. 



Origin. In the tissues and blood of yellow-fever patients. 



Form. A small bacillus with rounded ends, often arranged in 

 pairs, sometimes in threads, with lateral flagella. 



Properties. Motile, readily stained, decolorized by Gram's 

 method. Does not liquefy gelatine -nor produce glucose fermen- 

 tation. Aerobic. No acid reaction in milk. 



Growth. Gelatine plates ; white kidney -shaped colonies, with 

 a central darker portion or nucleus. 



Agar. Colonies look like drops of paraffin, with margins 

 raised above the surface. Kept alternately at 22 C. and 37 C., 

 the colonies take on a characteristic appearance, as if an im- 

 pression had been made in soft wax. 



