REACTIONS OF AMEBA TO LIGHT. 63 



shows that a beam of green light acts as a disturbing factor when 

 an ameba is stimulated at the same time by globulin. 



A grain of globulin and a beam of yellow spectral light were 

 placed to the right of the path of a proteus with the light between 

 the globulin and the ameba 397. As the ameba moved forward 

 it turned to the right and directly toward the yellow light. The 

 ameba moved over the light, then turned to the left and moved 

 into contact with the globulin, which the ameba rolled around a 

 short distance before ingesting it in a normal food cup. The 

 yellow light did not disturb the ameba when stimulated simul- 

 taneously by globulin. 



A grain of globulin and a beam of yellow light arranged as in the 

 preceding experiment were placed in the path of another proteus 



408 but the behavior observed was negative, due doubtless 

 to lack of hunger in the ameba. The ameba was in Y-shape at 

 the beginning of the experiment 408. The ameba responded 

 negatively by bending the right prong to the right and flowing 

 along it. A pod was thrown out on the right, indicating the 

 presence of a tendency to a positive reaction. The ameba was 

 then shifted with the yellow beam straight ahead and the globulin 

 a little to the left 412. The tip of the ameba forked, the axes 

 of the limbs coinciding with the same straight line, and nearly 

 perpendicular to the rest of the ameba 413. The right prong 

 turned toward the yellow light 415 and presently two pseudo- 

 pods were sent out a short distance toward the globulin 416 



but both were withdrawn as the ameba moved away through a 

 pseudopod thrown out on the right 417. The ameba was shifted 

 with the globulin straight ahead and the beam of yellow light to 

 the left 419. The ameba moved forward a short distance 

 when a pseudopod was thrown out to the left 421. This 

 pseudopod became the main one, and after it flowed ahead some 

 distance it turned to the right and moved toward the globulin 



423. The tip of the ameba then turned to the right still more 

 strongly and at the same time a pseudopod was thrown out in the 

 direction of the stimulating objects 424. The posterior end 

 now became activated but only for a short time 425. Several 

 new pseudopods were formed indicating uncertainty in behavior, 

 of which the one on the right extending toward the globulin 



