The Chemistry of Light-Production in Luminous Organisms. 



229 



3. EFFECT OF TEMPERATURE ON THE REACTION. 



A very faint light is produced when pyrogallol + H 2 O 2 at C. is mixed 

 with potato-juice at C. The light is much brighter at 5 and quite 

 bright at 10 C. Pyrogallol + H 2 O 2 mixed with blood (1 per cent) 

 gives no light at 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 -f H 2 O 2 , and guaiac + ionized 

 turpentine, are also recorded. Similar results were obtained with 

 turnip-juice. Blood does not lose its power to oxidize pyrogallol +H 2 2 

 with light-production or guaiac +H 2 2 , even after 10 minutes' boiling. 



TABLE 23. 



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

 ence of H 2 2 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 HC1. 



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

 pyrogallol + 1 c.c. 3 per cent H 2 O 2 ) and (potato-juice + KCN or 

 NaOH or HC1) were mixed. Table 24 gives also the effect of catalase on 

 the bluing of guaiac + H 2 2 , 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. 



