KINETICS OF THE BIOLUMINESCENT REACTION IN 

 CYPRIDINA. II. 



By WILLIAM R. AMBERSON. 



{From the Physiological Laboratory, Princeton University, and the Laboratory of 

 Pure Science, Nela Research Laboratories, Cleveland, Ohio) 



(Received for publication, March 22, 1922.) 

 EXPERIMENTAL RESULTS. 



1. Nature of the Curve of Decay in Cypridina Luminescence. 



The Initial Flash. — A striking feature, observed in practically every 

 photographic record which I have taken, is the occurrence of a very 

 bright initial flash of light, produced at the instant of the union of 

 luciferase and luciferin solutions, and lasting usually for not more 

 than 2 mm. of film, or half a second. An inspection of the plate 

 will indicate the nature of this flash in terms of its photographic 

 effect. The observed initial light intensities in two good typical 

 records are shown in Tables I and II. These values are to be con- 

 trasted with the calculated values in the parallel column, which 

 would be consistent with intensity values read from 10 mm. on to 

 the end of the record, which are connected by a simple mathemetical 

 relationship soon to be discussed. The initial flash is shown graphi- 

 cally in Fig. 1, where it is indicated by the dotted line at the beginning 

 of the curve. 



The significance of this flash is problematical. I have been unable 

 to detect any law by which its magnitude may be predicted. I 

 have very often obtained a practical identity in the values for the 

 initial readings on two simultaneous records whose later courses are 

 quite dissimilar. Yet this is by no means a constant observation, 

 and may have no special significance. It should be recalled that the 

 general practice of the physical chemist, in the study of chemical 

 kinetics, is to allow any reaction a brief space of time at least, to 

 straighten out, before measurements are begun. 



The Law of Decay. — In an attempt to follow the kinetics of a 

 chemical reaction by the measurement of light intensities emitted 



535 



