98 FRED W. TANNER 



glucose broth and production of fluorescent pigment is probably 

 bound up with the structure of pyocyanin and its formation by 

 the bacterial cell. If the opinion of Ledderhose is accepted that 

 this pigment is a derivative of the anthracene group, it is possible 

 that no apparent relation exists. The fluorescent bacteria pro- 

 duce a green diffusible pigment along with which there is a large 

 amount of ammonia. The pigment itself is probably basic in 

 character. 



SUMMARY 



1. Of a series of 100 strains of fluorescent bacteria, isolated 

 from water, all cultures correlate with regard to the production 

 of fluorescent pigment, (produced very profusely when the 

 bacteria are grown in Frankel's solution), formation of acid in 

 glucose broth, absence of diastasic action upon potato starch, 

 negative indol formation and non-fermentation of sucrose and 

 lactose. 



2. These cultures, when studied according to the group num- 

 ber as expressed on the descriptive chart of the Society of 

 American Bacteriologists, fall into 27 groups. 



3. The fluorescent bacteria are about evenly divided with 

 regard to gelatin liquefaction. The test is not delicate when 

 applied to this group and requires further study. 



4. Four of the 100 strains are spore formers. This charac- 

 teristic is recognized as one which logically separates a bacterial 

 species. 



5. With the exception of the four spore formers, the fluores- 

 cent bacteria in water, as indicated by this study, constitute a 

 homogeneous group of bacteria, difference appearing only in 

 regard to gelatin liquefaction, formation of hydrogen sulfide 

 and perhaps fermentation of glycerol. 



It is a pleasure to acknowledge my indebtedness to Prof. 

 Edward Bartow and Prof. H. A. Harding for their personal 

 interest and valuable suggestions throughout this work. 



