REACTIONS OF AMEBA TO LIGHT. 57 



violet light on the left 241. As the ameba moved forward 

 past the light a small pseudopod was sent out toward the light, 

 but it was withdrawn before it came into contact with the light. 



When shifted again with the light on the right 245 the 

 ameba sent out a pseudopod anterior to the light 249 but 

 it curved backwards toward the light as the ameba moved for- 

 ward 251. On the next trial 253 the ameba first turned 

 away from the light then sent out a pseudopod directly into 

 contact with it; then another pseudopod was sent out on the 

 side and anterior to this one. 



Summary. Amebas react positively, negatively, or indiffer- 

 ently toward violet light. The greater number of changes of 

 behavior produced by violet light were positive. No definite 

 differences could be observed between the effects of violet light 

 and those of any other spectral light thus far described. 



Green Light. A beam of green spectral light was projected to 

 the right of an Amceba dubia 259. As the ameba moved forward 

 the tip of the main pseudopod moved to the left. A small 

 pseudopod was formed on the right toward the light. The 

 ameba then turned toward the right and at the same time threw 

 out a pseudopod on the right near the tip of the main pseudopod. 

 Both pseudopods were withdrawn as the ameba moved on. 

 (Compare the behavior of this ameba with that illustrated in 

 Figs. 219-222.) 



The beam of green light was then projected to the right of a 

 proteus 262-265. As the ameba moved forward, a large 

 pseudopod which was thrown out on the left, was soon retracted, 

 the ameba moving on in a straight path. The ameba was shifted 

 266-270 with the green light to the right. As the ameba moved 

 on past the light, a small pseudopod appeared on the right near 

 the light, but it was retracted before it had developed to any 

 extent, as the ameba flowed on. 



These few experiments indicate that the effect of green spectral 

 light is similar in a general way to that of white, red, blue, etc. 

 Although the positive reactions in these experiments are slight,, 

 they are nevertheless definitely positive. If I had made as 

 many experiments with green light as with red or blue, I have 

 no doubt that more decided reactions would have been obtained. 



