PRODUCTS OF VITAL ACTIVITY. 145 



widely distant sources, are similar in their morphological and bio- 

 logical characters, and at least belong to the same group. In a com- 

 munication made in 1891 Winogradsky arrives at the conclusion 

 that the ferments which cause the oxidation of ammonia and pro- 

 duction of nitrites are not capable of producing nitrates, but that 

 other microorganisms are concerned in the oxidation of nitrites. 

 In sterilized soil to which a pure culture of his nitromonas was 

 added nitrites only were produced, and the presence of various 

 microorganisms common in the soil did not result in the forma- 

 tion of nitrates so long as the specific ferment was absent to which 

 this second oxidation is ascribed (nitrifying bacillus of Winograd- 

 sky). 



Phosphorescence. Several different bacteria have been studied 

 which, in pure cultures, give rise to phosphorescence in the medi- 

 um in which they are cultivated. In gelatin cultures the light 

 is sufficient in some instances to enable one to tell the time by a 

 watch in a perfectly 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- 

 cens from sea water in the vicinity of the West Indies gives the 

 most striking results, especially when planted upon the surface 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 harbor at Kiel, and the other a widely distributed species 

 called by Fischer Bacterium phosphorescens. Katz (1891) has de- 

 scribed 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. 

 10 



