284 



STUDIES ON BIOLUMINESCENCE. IX 



and tannic acid precipitates can be dried and will again give light 

 with lucif erase if redissolved. 



TABLE III. 

 Properties of Photogenic Substances. 



Property. 



Alkaloidal 

 reagents 



Phosphotungstic acid. 



and acetic acids, 

 acid and HCl . . . 



Tannic acid. 



and acetic acids, 

 acid and HCl. . . - 



Picric 



" and acetic acids. ... 

 " acid and HCl 



^ K4Fe(CN)6 and acetic acid. 



Heavy metal 

 salts 



Basic lead acetate . . . 

 Neutral lead acetate. 



" " " and acetic 



acid 



Mercuric chloride 



" " and acetic 

 acid 



Uranyl nitrate and acetic acid. . 



Acids and 

 alkalies 



NaOH 



NH4OH 



Acetic acid 



H2CO3 



Trichloroacetic acid. 



Luciferase. 



Completely pre- 

 cipitated. 



Nearly com.pletely 

 precipitated. 



Nearly completely 

 precipitated. 



Completely pre- 

 cipitated. 



Nearly completely 

 precipitated. 



Not precipitated. 



Not precipitated. 



Lucif erin. 



Very nearlj^ com- 

 pletely precipi- 

 tated. 



U it <£ 



Completely precipi- 

 tated. 



Nearly completely 

 precipitated. 



Not precipitated. 



Not completely 

 precipitated. 



Not precipitated. 

 Not completely 

 precipitated. 



Almost completely 

 precipitated. 



Not - completely 

 precipitated. 



Not precipitated. 



Picric acid added to luciferin solution gives no good precipitate but 

 only an opalescence or turbidity. This is true even when picric acid 



