11-.' PROMPTS OF VITAL ACTIVITY. 



watch in a |*?rfectly dark room, and such cultures have even been 

 photographed by their own light. 



The phosphorescence is influenced by changes in the culture 

 medium and by conditions of temperature, but we have no exact 

 knowledge of the mode of its production. The Bacillus phosphores- 

 < ins from sea water in the vicinity of the West Indies gives the 

 must striking results, especially when planted upon the surf ace of 

 cooked fish and placed in an incubating oven at 30 C. Two other 

 species have been studied by Fischer one obtained from the water 

 of the- harl>or at Kiel, and the other a widely distributed species 

 ailed by Fischer Bacterium phosphorescens. Katz (1801) has de- 

 - -rilied several species obtained by him from sea water and from 

 phosphorescent fish in the markets at Sydney, New South Wales 

 Bacillus smaragdino-phosphorescens, Bacillus argenteo-phosphores- 

 cens, Bacillus cyaneo-phosphorescens, Bacillus argenteo-phosphores- 

 cens liquefaciens. 



