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J. E. BRUGGER 



were usually suspended in water, though buffers and other solutions 

 were also used. Water was preferred because it simplified the problem 

 of attaining an equiUbrium with the flushing gas and thus facilitated 

 the changing from one gas mixture to another. 



IRRADIATION INTENSITY 



Fig. 1. Fluorescence intensity versus irradiation intensit}- for Chlorella in water 



swept with various gas mixtures. 



4 



The anomalies of fluorescence yield during induction periods, pre- 

 viously reported by others, were observed. However, all measure- 

 ments reported here are steady-state values. Generally the fluores- 

 cence was measured by starting at low intensities of irradiation and 



