30 



JACQUES LOEB AND HARDOLPH WASTENEYS 



orange and yellow rays) are absolutely ineffective; that the 

 rays for 5300 to 4900 (i.e., yellowish-green, green, and greenish- 

 blue) are only slightly effective; while the rays of the wave length 

 of Jf.735 A.U., (i.e., blue) constitute the optimal portion; and that 

 in the indigo the efficiency diminishes again. This result is al- 

 most identical with the one obtained by Blaauw with the seed- 

 lings of oats (table 3). 



TABLE 3 

 Experiment 2: Exposure, five minutes 



This result was less striking than the previous one through 

 the combination of two circumstances: (1) The material was 

 more sensitive than that used in the previous experiment, and 



