522 Bulletin 167 



various widely separated groups, the early writers recognizing 

 the ability to form the fluorescing pigment as a valuable diagnostic 



character, but apparently failing to consider a possible phylo- 

 genetic relationship. In the light of the intimate relationship 

 revealed by the more critical studies of the later investigators, all 

 green fluorescent bacteria are now classified in the Pseudomonas 

 group of Migula. Moreover it is now recognized that many of 

 the described species are identical, while the characters of others 

 grade into each other so imperceptibly that present bacteriological 

 methods fail to demonstrate specific constant differences upon 

 which differentiation may well he based. 



The members of the group are widely distributed. They 

 are almost universally found in the presence of putrefying organic 

 material, and are abundant in soil, water, and air. They are 

 recognized as one of the most common types of water bacteria. 

 vSchmelck (26:546) noted that the predominating organisms in 

 glacial waters were of this sort, and Harrison (12) and Belli (2 \ 

 observed B. fluorcscens liqucfaciens in hail. Jensen (13:613) 

 states that the fluorescent organisms occur in butter, while Thdni 

 (30:623) noted their presence in fifteen samples of lemonade 

 which he analyzed. Griffon (11) claims that B. fluorescens lique- 

 faciens and B. fluorescens putrida are capable of producing wet 

 rots of certain vegetables. The former lias been reported as the 

 causal organism in a carrot rot. while tobacco anthracnose is 

 attributed to B. aeruginosas, which according to Griffon, is 

 synonymous with B. fluorcscens putrida. Tomatoes grown under 

 glass have also been attacked by a stem canker said to be 

 due to B. fluorescens. Although the majority of fluorescent bac- 

 teria are harmless, certain species are reported as pathogenic to 

 animals. It is therefore evident that the bacteria of this group 

 are capable of existing' under a variety of conditions. 



Fluorescent bacteria play a leading role in the deterioration 

 of maple sap. Fresh drawn sap of the early "runs" is water clear 

 and has a clean sweet flavor, but with the advent of warmer 

 weather it becomes more or less cloudy and a disagreeable flavor 



