104 THE NATURE OF ANIMAL LIGHT 



squid, Watasenia; and the fish, Monocentris japonica. 

 E. B. Harvey (1917) could not demonstrate them in 

 Noctiluca. There are several reasons why the existence 

 of such bodies might be difficult to demonstrate, but these 

 reasons cannot be considered here. We thus see that the 

 photogen is in reality of dual nature, that two substances 

 are necessary for light production and that they may be 

 very readily separated because of difference in resistance 

 to heating. In this respect Bioluminescence is similar to 

 some other biological processes, notably to certain immune 

 reactions and to certain enzyme actions. 



Thus, for the haemolysis of foreign red blood cor- 

 puscles, a specific immune body {amboceptor or substance 

 sensibilatrice) not destroyed by moderate heating, and a 

 thermolable complement (alexin) are necessary. 



For the alcoholic fermentation of glucose by the zymase 

 of yeast juice two substances are also necessary. The 

 zymase is made up of a heat resistant, dialyzing com- 

 ponent, the co-enzyme, and a non-dialyzing substance, 

 destroyed on boiling, the enzyme proper. Both must be 

 present for alcoholic fermentation of glucose to proceed 

 and the two may be separated by dialysis or by their dif- 

 ference in resistance to heating. Several other character- 

 istics of living cells are known to depend on the joint actioii 

 of two substances, one thermolabile, the other thermo- 

 stable. The reducing action of tissues, according to 

 Bach, requires a reducing enzyme proper or perhydridase 

 and some easily oxidizable substance, such as an aldehyde. 

 The aldehyde has been spoken of as the co-enzyme. 



Because of the necessity of thermostable and thermo- 

 lable substances for light production in luminous animals 

 and because I was unable to oxidize the thermostable 



