w. D. Mcelroy and j. w. Hastings 179 



arations after ATP has been added. The results reported in Table V 

 indicate that the most effective compounds are the inorganic meta- 

 and pyrophosphoric acids. It is important that none of the compounds 

 listed will initiate luminescence in the dark preparations. 



24 — 



TIME (MINUTES) 



Fig. 12. The response of the luminescent system to varying inorganic triphos- 

 phate concentrations and a constant ( 2 X 10* M ) ATP concentration ( McEl- 

 roy, 1951a). 



A series of experiments has been performed with varying concentra- 

 tions of ATP and inorganic triphosphate in an effort to learn more 

 about the kinetics of the stimulation phenomena. The results of these 

 experiments are presented in Figs. 11 and 12. They demonstrate that 

 the initial luminescent response varies with the ATP concentration 

 up to approximately 0.0002 M. The maximum response to a constant 



