290 YELLOW FEVER; BUBONIC PLAGUE; INFLUENZA. 



development on the agar in a distinctive manner. Sanarelli 

 advises an exposure of from twelve to sixteen hours to the 

 incubator temperature, and then an exposure to the room 

 temperature for the same length of time. The colonies look 

 like a drop of milk. They are transparent and bluish, with 

 a dark centre like a nucleus. 



Glucose and saccharose are fermented. Indol is formed 

 in solutions containing peptone. Milk remains unchanged. 

 Bacillus icteroides lives for a long time in sea-water, but dies 



FIG. 130. 



Bacillus icteroides. (Sanarelli.) 



in ordinary water. It succumbs to light, but resists 

 desiccation. 



Sternberg's Bacillus X stains with Gram's stain and pro- 

 duces a luxuriant growth on potato ; otherwise it is apparently 

 identical with Bacillus icteroides. 



Pathogenesis : Bacillus icteroides is pathogenic for both man 

 and animals. When injected into the ear vein of an animal, 

 it produces the identical lesions seen in yellow fever cadavers. 

 According to Sanarelli, infection takes place through the 



