STUDIES ON BIOLUMINESCENCE. 

 XIV. The Specificity of Luciferin and Luciferase. 



By E. NEWTON HARVEY. 



(From the Physiological Laboratory, Princeton University, Princeton, and the 



Department of Marine Biology, Carnegie Institution of Washington, 



Washington, D. C.) 



(Received for publication, October 15, 1921.) 



introduction. 



In the living world are found more than thirty groups of organisms 

 producing light, scattered, in the animal kingdom at least, through 

 orders widely different in morphological characteristics. Physio- 

 logically, one order may contain individuals producing light in quite 

 different ways, as the squids, some of which have light organs pro- 

 ducing an external secretion of luminous material, while others possess 

 light organs of internal combustion. Among the fish, also, are 

 found various types of luminescence. Some forms emit light only 

 as a result of stimulation while others luminesce continually day and 

 m'ght, and the intensity is quite independent of stimulation of any 

 kind. In this respect these fish resemble the fungi and luminous 

 bacteria which also emit a steady continuous light which is not varied 

 on stimulation. 



While it is impossible at the present time, because of lack of data, 

 to classify accurately and logically the various types of luminescence 

 found in living things, the accompanying list is an attempt in this 

 direction, which will serve as a guide to the groups, whose particular 

 characteristics of luminescence are discussed in this paper. Accord- 

 ingly, relationship as well as physiological peculiarities of lumines- 

 cence have been considered in making the group (Table I). 



Two questions at once arise in connection with these data. The 

 first has to do with the presence of the luciferin-luciferase reaction. 

 As is evident from the above list, luciferin and luciferase, first dis- 



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