Animal Instincts and Tropisms 263 



Froschel 1 and by Blaauw. 2 In the following table 

 are given the results of Blaauw's experiments on the 

 applicability of the Bunsen-Roscoe law for the helio- 

 tropic curvature of the seedlings of oats (Avena sativa). 

 The time required to cause heliotropic curvatures for 

 intensities of light varying from 0.00017 to 26520 

 metre-candles was measured. The product it, namely 

 metre-candles-seconds, varies very little (between 16 

 and 26). 



TABLE VII 



It is, therefore, obvious that the blind instinct 

 which forces animals to go to the light, e. g., in the case 

 of the moth, is identical with the instinct which makes 



1 Froschel, P., Sitzungsber. d. k.Akad. d. Wissensch.,'Wier\, 1908, cxvii. 

 a Blaauw, H. A., Rec. d. travaux botaniques Neerlandais, 1909, v., 209. 



