WILLIAM R. AMBERSON 557 



exist for both enzyme and substrate in the bodies of luminescent 

 forms. We have already seen that even in vitro, with comparatively 

 dilute enzyme solutions, the velocity constant reaches a very high 

 value. In those luminescent forms in which the mixing of luciferase 

 and luciferin occurs within the body, concentrations must be much 

 higher, and the reaction must be still further greatly accelerated, so 

 that the hght is confined practically to a single momentary flash. 

 Even in Cypridina where the luminescent materials are ejected into 

 the sea water, these must be very narrowly localized, and the velocity 

 of reaction and the intensity of the light produced, must be far 

 higher than we can secure in our laboratories. These bioluminescent 

 reactions give a beautiful visual demonstration of the swiftness and 

 efficiency of organic catalysis. 



SUMMARY. 



1. The decay curve of the light produced in the course of the lumi- 

 nescent reaction in Cypridina is, after the first second, in complete 

 agreement with the theoretical expectation for a monomolecular 

 reaction, if light intensity at any instant is assumed to be propor- 

 tional to reaction velocity at that instant. It is shown that for such 

 a reaction 



log 7 = — kt -{• log Ak 



and that the experimental values satisfy this equation. 



2. The first second or two of the reaction is characterized by a 

 brilliant initial flash, whose value is much too high to accord with 

 the succeeding intensities and with the above formula. It is suggested 

 that this initial high reaction velocity is an indication of a hetero- 

 geneous system. 



3. Identical solutions run simultaneously give decay curves which 

 check within the limits of the photographic error. 



4. Stirring does not affect the reaction velocity or the form of the 

 decay curve. 



5. Reaction velocity is proportional to enzyme concentration, over 

 the range of concentrations used in the study. 



6. Changes in the concentration of the substrate do not aJfTect the 

 value of k, when all other factors are held constant. A diminution 



