34 



JACQUES LOEB AND HARDOLPH WASTENEYS 



4800 and above is less than that of wave length 4700. It is 

 possible but not certain that there are solarization effects. 



In the next series of experiments a region in the neighborhood 

 of 5600 A.u. in the yellow towards the yellowish-green was 

 selected for the stems (table 10). 



TABLE 10 



Experiment 8: Eudendrium ex- 

 posed various lengths of time 

 to the same wave length {about 

 5600 A.u.) . 



In order to make sure that this negative result was not the 

 fault of the material experiments with the same lot of material 

 were carried out in the blue-violet part of the spectrum (table 

 11). 



TABLE 11 



Eudendrium exposed for one hundred and fifty minutes 



This experiment again shows strikingly that the blue and vio- 

 let part of the spectrum is the effective one. The region between 

 4700 and 4750 A.u. is again the most efficient. 



In a third experiment of this series the stems were exposed 

 to a wave length of about 4900 A.u. (blue towards the green) 

 for various periods of time with the result shown in table 12. 



