340 



UGHT AND THE BEHAVIOR OF ORGANISMS 



In another series of experiments in which one half of 

 one dish was covered with a ruby glass and that of another 

 dish with blue glass, the majority of the animals collected 

 in the uncovered portion of both dishes. It is evident 

 from the results in troughs 3 and 4 above that the daph- 

 nias were positive to the highest light intensity used in 

 these experiments. It may then be assumed that they 

 were positive to the light conditions in which the majority 

 collected in troughs i and 2, and in the experiments with 

 red and blue. In the former however they collected in 

 the part of the trough having the lower intensity, i.e., in 

 the green and yellow respectively, in preference to white, 

 whereas under all the other conditions they collected in 

 that portion of the trough having the higher light intensity. 



While these results do not demonstrate subjective color 

 sensation, I am unable to see how they can be explained 

 without assuming a specific effect depending upon the 

 length of the waves or the color iadependent of intensity 

 or brightness. 



Lubbock's conclusions are very cautiously summed up 

 in the following paragraphs (p. 231): 



" My experiments, I think, show that while the Daph- 

 nias prefer light to darkness, there is a certain maximum 

 of brilliancy beyond which the light becomes inconven- 



