The Chemistry of Light-Production in Luminous Organisms. 

 3. Effect of Temperature on the Reaction. 



229 



A very faint light is produced when pyrogallol + H2O2 at 0° C. is mixed 

 with potato-juice at 0° C. The Hght is much brighter at 5° and quite 

 bright at 10° C. Pyrogallol + H2O2 mixed with blood (1 per cent) 

 gives no light at 0° C, but a very faint light at 2° C. 



High temperatures destroy the pyrogallol oxidase of potato-juice. 

 This occurs between 80° and 85° C., as indicated in table 23. The 

 potato-juice was rapidly heated to the temperatures 50°, 55°, 60° C, 

 etc., then cooled rapidly in running water. The destruction of cata- 

 lase, the formation of a precipitate in the potato-juice, and the effect 

 on its power to blue guaiac alone, guaiac + H2O2, and guaiac + ionized 

 turpentine, are also recorded. Similar results were obtained with 

 turnip-juice. Blood does not lose its power to oxidize pyrogallol +H2O2 

 with light-production or guaiac+H202, even after 10 minutes' boihng. 



Table 23. 



Note from table 23 that the pyrogallol and guaiac oxidases in pres- 

 ence of H2O2 are both destroyed between 80° and 85° C, but that with 

 ozonized turpentine the juice heated to 100° C. still blues guaiac faintly. 

 The natural peroxide (oxygenase) of potato-juice, which disappears on 

 standing, is destroyed more readily than the peroxidase. Catalase 

 is destroyed between 55° and 60° C. before a precipitate has appeared, 

 whereas peroxidase is still active after a precipitate has appeared. 



4. Effect of KCN, NaOH, and HCl. 



In testing the effect of these substances, equal parts of (1 c.c. m/160 

 pyrogallol + 1 c.c. 3 per cent H2O2) and (potato-juice + KCN or 

 NaOH or HCl) were mixed. Table 24 gives also the effect of catalase on 

 the bluing of guaiac -f- H2O2, and the color of indicators added to deter- 

 mine the amount of acid or alkali uncombined with protein. Neutral 

 red is red in neutral or acid solution, yellow in alkalies. "Di-methyl" 

 is yellow in neutral or alkaline solution, red in free acid solution. 



