WILLIAM R. AMBERSON 539 



enzyme and substrate all indicate clearly that in every case after the 

 first bright flash is over, the emitted light dies out by a simple expo- 

 nential relationship, so that if the logarithm of the intensity of the 

 light be plotted against time a straight hne may be drawn through 

 all the points. A graph of the intensity values obtained in a typical 

 decay curve is shown in Fig. 1, these values being the same as those 

 tabulated in Table I. In yl, intensity is plotted against time; in B 

 the logarithm of the intensity is plotted against time. The expo- 

 nential relationship is unmistakable. I have found this relationship 

 holding in a large number of separate records, totaling 48 to date 

 The coincidence between the experimental values and those calcu- 

 lated from the mean curve is not always as good as in the records 

 tabulated in Tables I and II, but is not to be mistaken. I have 

 plotted all other records submitted in the straight line form only, 

 since this form is best adapted to mathematical analysis. 



In Tables I and II the calculated values are those taken from the 

 mean curve of the straight line form. The calculated initial inten- 

 sities are read from the intersection of the straight line on the zero 

 time axis, and are about one-third of the intensities actually recorded 

 in the initial flash. 



The form of the decay curve in Cypridina is in complete agreement 

 with the theoretical expectation for a monomolecular reaction. For 

 if, according to the standard form, 



dx , , 



Where k = velocity constant, A, initial concentration of the single 

 reactant, and X, amount of this reactant which has disappeared in 

 the reaction in time t. 

 Then by integration 



k = — log 



kt = log A - log (A - X) 



And 



(1) log {A - X) =log^ -kt 



Let / represent light intensity. Then, by the basic assumption 



dx 

 / = - = t(..-.V) 



