CHROMOGEXIC BACTERIA 195 



above, produce two pigments; namely, pyocyanin and 



iluorescin. Ledderhose analyzed pyocyanin and found it 



to ho similar in structure to some of the known ptomains 



C ir.4\ : O\ It seems to be drived from the aroma tics and 



oly related to the anthracines. Pyocyanin is non- toxic to 



animals. 



When treated with acids, fluorescin becomes colorless 

 and pyocyanin turns red. Soluble phosphates and sulphates 

 seem to he necessary for the production of fluorescin but not 

 pyocyanin. Pyocyanin can be produced in media devoid of 

 protein. 



lv :h pyocyanin and fluorescin are soluble in water. Pyo- 

 cyanin is also soluble in chloroform but insoluble in alcohol, 

 and tluorescin is insoluble in both alcohol and chloroform. 



Pigments Insoluble in Water. Soluble in Alcohol. The 

 Mvrococcus pyogenes vars, aureus, citreus, flavus, and 

 Iv.cillus prodigiosus are typical examples of chromogenic bac- 

 teria of this class. 



1: is claimed by those investigators who have studied the 

 pigment granules of this class that they are fat-like in nature 

 and similar to lipochromes. They are soluble in all fat solve 



dendritic crystals, can be saponified, and on decomposi- 

 tion give the acrolein reaction. T H,O and fat odors. When 

 sulphuric acid is added, the lipocyanin reaction 

 occurs and the pigment granules are changed to blue. 



Pigments Insoluble in Water and Alcohol. Very few 

 -.ctoria belong to this class. Wells mentions the 



