230 



JACQUES LOEB AND HAKDOLPH AVASTENEYS 



parison, after another black cardboard with openings at R and 

 Ri, to let the two beams of light pass, had been put over the box, 

 and the first cardboard enclosing the animals had been removed. 

 The organisms collected at g were now under the influence of 



Euglena viridis 

 Wave lengths in yu/^ 



4 552 569 5?7 60 5 62 25 6J0„ 



these two beams coming from different directions. As stated 

 before, they moved towards R and Ri according to the selective 

 efficiency of the two beams of light. The readings were taken 

 after from 15 minutes to 3 hours or more to make sure that the 

 results were permanent. Before a new experiment was made 



