GREEN FLUORESCENT BACTERIA FROM WATER 97 



Investigations with regard to better technique for determining 

 gelatin Hquefaction are under investigation in this laboratory. 



The strains are all reported as facultative anaerobes. This is 

 another determination called for in the group number for which 

 there is no satisfactory technique. Formerly much importance 

 was attributed to growth along the hne of inoculation in stab 

 cultures. This is beset with too many objections. A medium 

 itself may contain sufficient dissolved oxygen to support growth. 

 Evidence of growth in 'the closed arm of the fermentation tube 

 has also been used to determine anaerobiosis. This limits the 

 determination to the particular substance from which the oxygen 

 was taken. A standard technique for this determination would 

 have much significance. 



With regard to diastatic action on starch, the personal equa- 

 tion is given too much importance in recording this characteristic 

 on the Society's chart. 



All of these cultures correlate with regard to fermentation of 

 glucose, production of fluorescent pigment, absence of diastasic 

 action on starch, negative indol formation, and probably non- 

 fermentation of sucrose and lactose. The modes in the curve 

 of Diagram II indicate that there is probably one type of action 

 on lactose and sucrose and possibly two types with regard to 

 glycerol. However, with glycerol one of these modes is quite 

 near the other and close to the line where experimental error 

 might connect it more evidently with the other. Since these 

 characters agree for so many cultures, all of which are from 

 widely separated sources, they are probably of significance. 

 The absence of diastatic action presupposes no amylase and 

 correlates well with the action on the other carbohydrates, lac- 

 tose and sucrose. As stated before, it is recognized that the 

 use of phenolphthalein as the indicator in determining reactions 

 is arbitrary, and that determination of true acidity by means of 

 the hydrogen electrode may prove that all of these strains were 

 unable to ferment carbohydrates. Negative indol formation 

 may indicate that peptone is not split to amino acids and other 

 products including tryptophan which is the precursor of indol. 



The explanation of the correlation between acid formation in 



