E; NEWTON HARVEY 209 



the use of reducing fluids which are not acid. If they also form 

 luciferin from oxyluciferin, a reduction must occur. Nascent H can 

 be generated by the action of NaOH on Al or when finely divided 

 Mg, Zn, or Al is placed in water. With Mg the water becomes only 

 slightly allcahne from the formation of almost insoluble Mg (0H)2. 

 If we add some Al powder and dilute NaOH to an oxyluciferin solu- 

 tion, H is given off and luciferin is formed. As oxyluciferin cannot 

 be formed by the addition of alkali alone we must have in this experi- 

 ment a reduction of oxyluciferin in alkahne medium by the nascent 

 H produced. Luciferin can also be formed by merely adding Al, 

 Zn, or Mg dust to an oxyluciferin solution. Methylene blue can be 

 readily reduced to its leuco base by Zn dust or Al plus NaOH 



Indeed, if one adds some Al, Zn, or Mg powder to a solution of 

 luciferase, Kght will appear whenever the solution is shaken. Luci- 

 ferase solution must always contain the oxidation product of luci- 

 ferin, oxyluciferin. In the presence of nascent H this is reduced to 

 luciferin and, since the reaction of the medium is alkaline and luci- 

 ferase is present, this is oxidized with Kght production, when, by 

 shaking, air is dissolved. The Kght can never become very bright 

 except at the surface because of the deficiency of oxygen in the solu- 

 tion. It would seem, then, that the action of bacteria, yeast, muscle 

 cells, etc. on oxyluciferin must be due not entirely to their acid reac- 

 tion but to their reducing power as well. 



The above experiment is striking and instructive. To a test-tube 

 of luciferase solution containing as it does oxyluciferin add some Zn 

 dust or Mg powder, and the evolution of hydrogen begins. Condi- 

 tions are now favorable for the reduction of oxyluciferin, and this 

 occurs. Shake the contents of the tube to dissolve oxygen and Hght 

 appears. AUow the tube to stand and the Hght soon disappears. 

 Shake again and the hght reappears. The reduction and oxidation 

 processes can be demonstrated many times. 



A similar experiment can be performed with luciferase plus oxy- 

 luciferin solution by the addition of (NH4)2S. This will serve also as 

 another example of the reduction of oxyluciferin in an alkahne me- 

 dium. Whenever we shake a tube of luciferase, oxyluciferin, and 

 (NH4)2S, hght will appear. When the tube is at rest it becomes 

 dark. Even the merest touch is sufficient to agitate the tube con- 



