The Chemistry of Light-Production in Luminous Organisms. 221 



Bacteria in oxygen-free sea-water do not glow, but will glow if oxygen 

 is admitted, even after a period of 24 hours. Bacteria in oxygen-free 

 sea-water to which toluol or ether is added will not glow if oxygen is 

 readmitted after 15 minutes. Hence the phosphorescent substance 

 undergoes decomposition in the absence of oxygen, a decomposition 

 not due to the toluol (compare the first statement in section 3), but 

 probably due to the action of some other substance. 



4. Moist luminous bacteria to which oxygenated distilled water is 

 added cease glowing, presumably because the photogen is rapidly 

 oxidized and used up when the bacterial cell is cytolyzed. 



Moist bacteria to which oxygen-free distilled water is added will not 

 glow even momentarily if oxygen be readmitted after 15 minutes, a 

 result again pointing to instability of the photogen when the cell- 

 structure is affected by cytolysis. 



5. Dried bacteria placed in oxygenated sea-water phosphoresce 

 momentarily, but if dried bacteria stand in contact with oxygen-free 

 sea- water for 15 minutes, no phosphorescence occurs when the oxygen 

 is admitted. Again (as in sections 3 and 4) the photogen has decom- 

 posed. It is, therefore, impossible to extract a phosphorescent sub- 

 stance from bacteria with oxygen-free aqueous solvents. 



6. Fat solvents extract nothing which will phosphoresce from the 

 dried bacteria. Some of the bacteria survive and will grow after such 

 extraction. Boiling alcohol, cold acetone, and ethyl butyrate destroy 

 the power to phosphoresce. 



7. Dried bacteria do not lose their power to phosphoresce after 24 

 hours' extraction with cold absolute alcohol, but moist bacteria (centri- 

 fuged) treated with 50 volumes of absolute alcohol, and then dried 

 rapidly, will not again phosphoresce if moistened. 



8. All attempts to separate the photogenic substance of luminous 

 bacteria into photogenin and photophelein have failed, due possibly to 

 the small amounts of these substances present at any one time. 



9. A photophelein can be prepared by absolute alcohol which will give 

 a faint hght with firefly photogenin, but attempts to obtain light with 

 firefly photophelein and bacterial photogenin prepared in various ways 

 have failed. 



10. The upper temperature-limit for luminescence is 38°; the lower 

 is —11.5°. Bacteria heated to 38° and cooled give only a faint light, 

 but bacteria will glow strongly if first cooled to liquid-air temperature 

 and then raised to room temperature. 



11. Oxidases for guaiac, a-napthol, para-phenylen diamine, phenol, 

 phenolphthalin, pyrogallol, or indo-phenol formers, if present, are 

 present in an endoenzyme condition. Catalase exists in luminous 

 bacteria. 



12. Luminous bacteria can not live if the osmotic pressure of the 

 medium fall below a certain value or if the salt-content of the medium 

 fall below a certain value. 



