THE CHEMISTRY OF LIGHT PRODUCTION 107 



the luminous organs with 90° alcohol in a closed vessel for 

 twelve hours and filtering (1896). (3) By heating the 

 viscid luminous fluid to 70° C. Apparently PJiolas 

 luciferin is sparingly soluble in alcohol as it can be ob- 

 tained either in an alcoholic extract (method 2) or by 

 precipitation with alcohol (method 1). Proluciferin 

 (called preluciferine in a later paper, 1917 a^ 1918 a), is 

 prepared by methods 1 or 2 except that fatigued siphons, 

 from which luciferin has been removed by washing, are 

 used (1907, 1917 a, 1918 a). Preluciferin can also be 

 obtained on boiling an extract of the luminous organ of 

 Pholas because luciferin (at 70°), luciferase (at 60°) 

 and a co-luciferase are all destroyed below the boil- 

 ing point (1917 a). 



Co-luciferase is prepared (1) by heating a luciferase 

 solution to 65° (1917 a) or (2) by extracting with water 

 portions of the siphon of Pholas which have previously 

 been macerated and well extracted with alcohol (1918 a). 

 Long-continued treatment with alcohol apparently de- 

 stroys the luciferase without affecting the co-luciferase. 

 On mixing a solution of preluciferin with one of co-lucife- 

 rase and allowing them to stand for 8-10 hours, luciferase 

 is formed and can be recognized by the fact that it will 

 give light with a crystal of KMn04. Preluciferine does 

 not do this. 



Recently Dubois (1918 a) states that preluciferine is 

 nothing but taurine and that taurine occurs in large quan- 

 tities in Pholas and is transformed into luciferine by the 

 action of co-luciferase. Not only taurine, but also Byla's 

 peptone, egg lecithin, and esculin can be converted into 

 luciferine by co-luciferase, and since esculin, a glucoside, 

 is so transformed, Dubois believes this proves that co- 



