The Chemistry of Light-Production in Luminous Organisms. 213 



In my experiments the moist bacteria have been broken up (cyto- 

 lyzed) in absence of oxygen by (1) oxygen-free distilled water and 

 (2) toluol. All marine cells can be cytolyzed by distilled water or fat 

 solvents. 



In the first method a dense mass of bacteria are placed in a vessel 

 from which the air is exhausted by an air-pump (see apparatus, p. 195). 

 The bacteria stop glowing, but reglow if air is again admitted. Then 

 oxygen-free distilled water is allowed to flow onto the bacterial mass 

 and it is thoroughly shaken. No light appears (indicating that the 

 water is oxygen-free), and 5 to 10 minutes later, if oxygen is added, 

 still no light is emitted. If there is a definite soluble photogenic sub- 

 stance in the bacterial cell it should have passed into solution in the 

 water when the cell was cytolyzed, and, provided no decomposition 

 took place, it should have glowed when oxygen was readmitted. Even 

 if we assume that the cell was not completely cytolyzed, the photogen, 

 if a stable substance, although one unable to pass the cell surface, 

 should have glowed within the cell. 



In the second method a dense emulsion of the bacteria in sea-water 

 is rendered non-luminous by removing the oxygen. Then a drop of 

 toluol is added without admitting oxygen (air). The emulsion is 

 shaken and no light appears. In a few minutes air is admitted and 

 still no light appears. Similar experiments with ether, chloroform, 

 and carbon tetrachloride gave similar results. Thus if the cells are 

 broken up the photogen disappears even though it has not been oxi- 

 dized, for no oxygen was present. The toluol itself does not destroy 

 the photogenic substance, as evidenced by the treatment of dried 

 bacteria with toluol. Luminous bacteria in oxygen-containing sea- 

 water to which a drop of toluol, ether, chloroform, or carbon tetra- 

 chloride is added very quickly stop phosphorescing. I explain this as 

 due to the fact that on cytolysis of the cell the oxidation processes run 

 riot and the available store of photogen is rapidly used up. The same 

 explanation may be applied to the loss of light in distilled water. We 

 may compare the conditions in bacteria to the conditions in a potato 

 cell. When the cells of the potato are crushed or when their surface 

 is destroyed by toluol or ether or chloroform, dark melanin oxidation 

 products are rapidly formed, but if the potato is cut and the cut cells 

 well washed to free them of their cell-contents, no blackening occurs, 

 although the lower intact cells at the cut surface are exposed to atmos- 

 pheric oxygen and only separated from it by their plasma membranes. 

 A destruction of these membranes would immediately cause oxida- 

 tions within to proceed rapidly. 



The conclusion drawn from the above experiments has been con- 

 firmed by allowing oxygen-free sea-water to come in contact with dried 

 bacteria in a hydrogen atmosphere. If, after 15 minutes, oxygen is 

 admitted, no glow is observed, although dried bacteria instantly glow 

 for a short time if moistened with oxygenated sea-water. 



