GREEN FLUORESCENT BACTERIA FROM vWATER 83 



1000 CO.; asparagin, 1 per cent; magnesium sulfate, 0.20 per 

 cent; dipotassium phosphate, 0.10 per cent. 



Growth in it was abundant but did not reach a maximum as 

 quickly as in Frankel's medium. None of these strains could 

 reduce the magnesium sulfate to hydrogen sulfide as determined 

 by the method described. 



Oxygen relations 



All strains were found to be facultative anaerobes. The 

 determination was carried out in a vacuum desiccator in the 

 bottom of which were placed about 50 grams of pyrogallol. 

 The cultures were made on agar slants and placed in the desic- 

 cator; and by means of a vacuum pump the pressure was reduced 

 as far as possible under these conditions. After this was done 

 a strong solution of KOH was allowed to be sucked into the 

 bottom of the desiccator by slightly opening the glass stop 

 cock. By this technique it is believed that a minimum supply 

 of oxygen was left. 



The desiccator was incubated for five days at room tempera- 

 ture, which was about 25°C. At the end of that time there was 

 visible growth. It was very restricted but quite apparent. 

 Some doubt was felt with regard to the results, since these 

 bacteria have always been described as strict aerobes, but since 

 growth was quite visible, the group number is determined on 

 the ground that they are facultative anaerobes and are able to 

 carry on a limited activity under reduced supplies of oxygen. 



Growth in plain milk 



This medium was made by thoroughly mixing 100 grams of 

 Merrell-Soule skim milk powder in 1000 cc. of distilled water. 

 It was then beaten with an egg beater, filtered and sterilized 

 in 75 cc. quantities in Erlenmeyer flasks. Inoculations were 

 made from twenty-four hour cultures and the flasks incubated 

 at 37°. The fluorescent bacteria seem to arrange themselves 

 into four general groups with regard to their action on milk. 



One group is made up of those cultures which produce prompt 



