79 



z 1/ 6 s /o /I /t/ /6 ^<^ ■^<> ^^ ^'/ -^<^ ze 3o 



Fig. I. Graphical representation of a case of positive photo-growth- 

 reaction (Table 111). The arrow gives the moment at which there was 

 illumination for 15 sec. with 14 metre-candle-power, on 8 sides. The 

 abscissa gives the time in minutes, the ordinate the ratio of the rates 

 of growth. 



