120 THE NATURE OF ANIMAL LIGHT 



Properties of Photogenic Substances from Cypridina — Continued 



Property 



Luciferaae 



Luciferin 



Alkaloidal Reagents 

 Phosphotungstio acid . 



Phosphotungstic and acetic 



acids 

 Phosphotungstic acid and 



HCl 

 Tannic acid 



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 



NHiOH 



Acetic acid 



H2CO3 



1 Trichloracetic acid 



Completely precipi- 

 tated 



Nearly completely 

 precipitated 



Nearly completely 

 precipitated 



Completely precipi- 

 tated 



Nearly completely 

 precipitated 



Not precipitated 



Not precipitated 

 Do. 

 Do. 

 Do. 

 Do. 



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- 

 cipitat-ed. 



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 



