184 The Animal Mind 



direction could they escape obstacles (130) ; but this fact they 

 would have to learn by experience, for which, in some cases 

 at least, they do not take time. Plateau believed the rising 

 into the air was due to sensations produced by the action of 

 the light on the surface of the body, leading the insects in 

 the direction of the strongest light, which usually comes from 

 above. He supported this view by showing experimentally 

 that a blinded insect would not rise if set free at night, while 

 on the other hand, if liberated in a lighted room, it would, in 

 spite of the blinding, fly toward the light or the lightest part 

 of the ceiling (332, 334). In the butterfly Vanessa, Parker 

 thinks the rising due to negative geotropism, as the insect 

 flew upward in a darkened room (307). Axenfeld suggested 

 that it might be caused by light penetrating the integument 

 of the head (7). 



72. The Psychic Aspect of Orientation to Light 



What shall be said of the psychic aspect of all this complex 

 mass of facts regarding the orientation of animals to light? 

 If such orientation occurs in some animals by the immediate 

 action of light on the body tissues, either by virtue of the direc- 

 tion of its course through them, or by the relative effects on 

 the motor apparatus, at symmetrical points, of stimulations 

 differing in intensity, there is no analogy for this in our own 

 experience. We are not pulled about into line by the direct 

 action of light on our bodies, and we cannot imagine what the 

 conscious accompaniment of such a process would be. If 

 orientation occurs through the giving of a negative reaction 

 whenever the body chances to move out of the oriented posi- 

 tion, we may conjecture that the negative reaction is, here as 

 elsewhere, accompanied by unpleasant consciousness ; whether 

 also by a specific visual sensation will be evidenced by the 

 existence of a sense organ or by any other of the arguments 



