No. 446.] PHOTINUS M ARGINELLL S. 



luminescence at ordinary temperature. By adding to liquid 

 No. 2 five or six times its volume of 959^ alcohol, or by boiling 

 it, a white floccose precipitate was formed and the mixture of 

 the remaining liquid with liquid No. i no longei' |)i-o(hu e(i light. 

 He therefore ctmsiders the white precipitate as lonstinnmg om- 

 of the two photogenic substances, the luciferase. I ,ut iterine \\;is 

 obtained in an impure state by evaporation of alcoholit n(|ui(l \o 

 t. Another experiment was tried with the lunnnDus nunoiis 

 secreted by Pholas. Two portions of the nuieous mixed with 

 water were taken, and one extinguished In' agitation, the othei 

 by bringing to the boiling point. The mixture of the result in- 

 obtained with the i)rothoracic organs of l\vroplionis iioitilunis. 

 One was extinguished l)y crushing, the other by dropi)iiig it into 

 boiling water. When the latter was crushed and mixed witii 

 the former, the light reai^peared. 



Dubois therefore states that he has estal)lislie(l expci inientally 

 that the light of living organisms is produced, in the i)resence 

 of water and oxygen, by the reaction j)etween lucifeiase. an 

 instable proteid substance ])ossessing in large measuie the 

 general properties of an enzyme, and luciterine. a chemical 

 substance. While Dubois confidently asserts that biological 

 light is not a result of oxidation, his experiments would not 

 seem to prove this conclusively. Me himself admits the neces- 

 sity of oxygen, and even if the proce->s i> not one ot >nni)le, 

 complete oxidation, it would yet seem i)rol)al)le that oxidation 



