212 C. F. CURTIS RILEY 



the light acts continuously. Further, it is not impossible that 

 a modified form of " trial and error" may function as the animals 

 travel toward or away from the source of illumination. In the 

 experiments with weak diffuse daylight, ray direction in the 

 field probably exerts comparatively little influence upon young 

 toads. 



Young toads react to light passed through red and blue solu- 

 tions by giving motor responses. When red light is employed 

 singly, it is noticed that the stimuli are not very effective. There 

 is a tendency for the animals to act negatively, both by turning 

 and jumping away from the light. The responses are less defi- 

 nite than when either white or blue light is used. When blue 

 light is employed the toads both turn and jump toward the 

 light, and they do so with more promptness, than is the case 

 when red light is used. When red and blue lights are used at 

 the same time, more animals jump toward the blue light than 

 they do toward the red light. Some toads jump toward the 

 red light, and a few individuals appear to be indifferent. 



Young toads subjected to light react to contact stimuli by 

 giving the motor response. If a stationary individual is stimu- 

 lated by another animal jumping against it, the former responds 

 either by turning or by jumping away. Frequently after such 

 a motor response, the animal follows it up by reacting to the 

 light. In the experiments with the lesser light intensities, the 

 young toads may respond to contact by several of them gather- 

 ing in the angles formed by the bottom and sides of the experi-* 

 mentation dish. They remain in such situations with their 

 bodies in close contact. 



Young toads frequently react with the death-feigning re- 

 sponse when handled with undue pressure and roughness. 

 During such response they remain immobile, with their legs 

 drawn up against the body. A toad may be caused to respond 

 in this manner by placing the animal on its back and holding^ 

 it in that posture for a few seconds. The length of the death- 

 feint varies in different individuals. If a toad has been made 

 to feign death in diffuse daylight, the response may be cur- 

 tailed by suddenly flashing a beam of light from the projection 

 lantern upon the animal. Young toads usually arouse from the 

 death-feint abruptly. A sudden tactual stimulus will effect this. 

 The death-feigning response may probably result in producing 



