SPECTRUM, HELIOTROPIC REACTIONS 



31 



(2) the number of polyps was so small that the error was greater 

 and the results not so uniform. Positive results were obtained 

 in the region between A.u. 4400 and 4735, that is, in the blue 

 and indigo and also possibly in the bluish-green; yellow was 

 ineffective, as before (table 4). 



The most effective region of the spectrum in this experiment 

 is again the region about 4735 in the blue, the same which has 

 proved the most effective in the two previous experiments. In 

 all the experiments red, orange and yellow, and extreme indigo 

 and violet, were ineffective. 



The next two experiments (4 and 5, tables 5 and 6) were made 



TABLE 5 

 Experiment 4-' Exposure to light, four minutes 



TABLE 6 

 Experiment 5: Exposure to light, three minutes 



