THE PRODUCTION OF FLUORESCENT PIGMENT BY 
BACTERIA. 
EDWIN O, JORDAN. 
A CONSIDERABLE number of different ‘‘species’’ of bacteria 
have been described as endowed with the property of forming a 
blue-green fluorescent pigment in suitable media. I append a 
list, perhaps not complete, of the various “fluorescent bacteria” 
already discovered. 
It is not at all likely that the fifty names bestowed upon 
these cultures represent as many totally distinct microorgan- 
isms, and in some cases it is practically certain that the same 
bacterium masquerades under several different titles. 
The experiments recorded in the present paper embody a 
series of attempts to discover the conditions under which fluor- 
escence is produced, and especially the nature and amount of 
the chemical substances essential to the formation of the fluor- 
escing body. 
I have chosen for this purpose six different cultures.’ Four 
of these do not liquefy gelatin and were sent to me from Kral’s 
Laboratorium under the names B. fluorescens albus, B. fluorescens 
tenuis, B. fluorescens mesentericus, and B. fluorescens putridus. The 
two others liquefy gelatin ; one of them was sent by Kral with 
the name B. viridans, and the second was isolated by me from 
the water of Lake Michigan and identified as B. fluorescens lique- 
faciens (description by Kruse in Fliigge’s Die Mikroorganismen 
2: 292). 
1. B. FL. ALBUS.— A bacillus was first described under this name by 
Zimmermann who found it in the Débeln water supply. The culture bear- 
*I have also made some experiments with B. pyocyaneus, but, owing to the com- 
plication due to the formation of at least two pigments by this bacillus, I am led to 
reserve my statements on this head for a subsequent communication. 
70. E. R. Zimmerman, Die Bakterien unserer Trink- und Nutzwasser 18, 
Chemnitz, 1890. : 
1899 ] 19 
