120 



THE NATURE OF ANIMAL LIGHT 



Properties of Photogenic Substances from Cypridina — Continued 



Property 



Alkaloidal Reagents 

 Phosphotungstic acid , 



Phosphotungstic and acetic 



acids 

 Phosphotungstic acid and 



HCl 

 Tannic acid 



Luciferase 



Completely precipi- 

 tated 



Tannic and acetic acids 

 Tannic acid and HCl. . . 

 Picric acid 



Picric and acetic acid 



Picric acid and HCl 



K4Fe(CN)6 and acetic acid 



Heavy Metal Salts 



Basic lead acetate 



Neutral lead acetate 



Neutral lead acetate and 

 acetic acid 

 : Mercuric chloride 



Mercuric chloride and acetic 



acid 

 Uranyl nitrate and acetic acid 



Adds and Alkalies 



NaOH 



._ NH4OH. 



Acetic acid 



H2CO3 



( Trichloracetic acid 



Nearly completely 

 precipitated 



Nearly completely 

 precipitated 



Completely precipi- 

 tated 



Nearly completely 

 precipitated 



Not precipitated 



Not precipitated 

 Do. 

 Do. 

 Do. 

 Do. 



Luciferin 



Very nearly com- 

 pletely precipitated. 



Very nearly com- 

 pletely precipitated. 



Completely precipi- 

 tated. 



Nearly completely 

 precipitated. 



Nearly completely 

 precipitated. 



Nearly completely 

 precipitated. 



Not precipitated. 



Do. 

 Do. 

 Do. 



Not completely pre- 

 cipitated. 



Not completely pre- 

 cipitated. 



Not precipitated. 



Not completely pre- 

 cipitated. 



Almost completely 

 precipitated. 



Not completely pre- 

 cipitated. 



Not precipitated. 

 Do. 

 Do. 

 Do. 

 Do. 



although almost completely salted out by (NH4)2S04, is 



strong evidence in favor of placing it in such a position. 



On the other hand, luciferin has two properties which 



to say the least are unusual for proteins. I refer to its 



