DEPARTMENT OF MARINE BIOLOGY. 



155 



lucif erase reaction. For this substance I propose to retain my old term 

 photophelein. 



When Cypridina luciferin is oxidized no fundamental splitting of the mole- 

 cule occurs, because the product, which I propose to call oxyluciferin, can be 

 readily reduced to luciferin again. This reduction is brought about under 

 conditions similar to those necessary for the reduction of dyes such as methy- 

 lene-blue. Indeed, the change luciferin — > oxyluciferin appears to be very 

 similar to the change leuco-methylene blue — > methylene blue. Oxyluciferin 

 can be reduced to luciferin, which mil again give light with luciferase by the 

 reductases of muscle-tissue, liver, etc., or by bacteria; by Schardinger's enzyme 

 of milk; by H2S or the nascent hydrogen from the action of acetic acid on 

 magnesium; and by palladium black and sodium hypophosphite, all well- 

 known reducing methods. The reaction luciferin <iii> oxyluciferin is a rever- 

 sible one and reduction of oxyluciferin no doubt occm-s in animals which 

 burn luciferin within the cell, thus tending for conservation of material. 



Table 1. — Properties of photogenic substances. 



Property. 



Luciferase. 



Luciferin. 



Salting out: 



By saturation NaCl 



By half saturation MgS04. . . 

 65- saturation MgS04 



Not precipitated 



....Do 



Nearly completely precipi- 

 tated. 



By saturation MgS04 and ace- 

 tic acid 



By half saturation (N2H4) 2SO4 

 By saturation (NH4)2S04. . . . 

 By saturation (NH4)2S04 and 



acet. acid 



Solubility in: 



Methyl alcohol 



Ethyl alcohol 



Ethjd alcohol, 90 p. ct 



Ethyl alcohol, 70 p. ct 



Ethyl alcohol, 50 p. ct 



Propyl alcohol 



Isobutyl alcohol 



Amyl alcohol 



Benzyl alcohol 



Acetone 



Acetone, 90 p. ct 



Acetone, 70 p. ct 



Acetone, 50 p. ct 



Ethyl acetate 



Ethyl propionate 



Ethyl butjTate 



Ethyl valerate 



Ethyl nitrate 



Glycerine 



Glycol 



Ether 



Chloroform 



Carbon disulphide 



Carbon tetrachloride 



Benzol, toluol, xylol 



Petroleum ether 



Anilin 



Glacial acetic . acid 



Slightly precipitated . . . . 

 Completely precipitated . 



Insoluble 



Do 



Do 



Do 



Slightly soluble . 



Insoluble 



Do 



Do 



Do 



Do 



Do 



Slightly soluble. 

 Fairly soluble. . 



Insoluble 



Do 



....Do 



.Do. 

 .Do. 

 .Do. 

 .Do. 

 .Do. 

 .Do. 

 .Do. 

 .Do. 

 .Do. 

 .Do. 

 .Do. 

 .Do. 



Not precipitated. 



Do. 

 Partially precipitated. 



Do. 



Not precipitated. 

 Nearlj' completely prec. 



Do. 



Soluble. 



Do. 



Do. 



Do. 



Do. 



Do. 

 Fairly soluble. 

 Slightly soluble. 

 Soluble. 

 Fairly soluble. 

 Soluble. 



Do. 



Do. 



Do. 

 Fairly soluble. 



Do. 

 Slightly soluble. 

 Very slightly soluble. 

 Soluble. 



Do. 

 Insoluble. 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 

 Fairly soluble. 



