REACTIONS OF AMEBA TO LIGHT. 67 



toward the dark spot until within about twenty microns 528 

 when the protoplasmic current was reversed and the ameba 

 moved off through a pseudopod on the left near the posterior 

 end 529. Soon this pseudopod was withdrawn and the ameba 

 flowed into another pseudopod (perhaps the vestige of the former 

 main pseudopod) which led the ameba to the right (to the left 

 of the dark spot) 533. After moving some distance in this 

 direction, a pseudopod was thrown out on the left directly 

 opposite to the dark spot 534. Two more pseudopods were 

 then formed on the right through the more posterior of which 

 the ameba moved on 535-537- A pseudopod was then formed 

 on the left which led the ameba out of range of the dark spot 538. 

 The ameba was then shifted with the dark spot on the right and 

 the grain of globulin just in front of it 540. The ameba turned 

 to the left 541 and sent out on the convex side a pseudopod 

 through which the ameba moved forward with the dark spot on 

 the left 543. As the ameba moved on it turned toward the 

 dark beam but presently two pseudopods were thrown out from the 

 middle of the ameba. one on either side 546. (The pseudopod 

 on the left was evidently formed to enable the ameba to move at 

 once into contact with the globulin; the one on the right was 

 formed without assignable cause, although opposite pseudopods 

 are frequently formed under conditions similar to these.) The 

 pseudopod on the left moved through a curved path to the left 

 into contact with the globulin 547-550. When the ameba 

 came into contact with the globulin, it was pushed into the dark 

 area. A slender pseudopod followed it while the tip of the main 

 one remained stationary for the moment, which indicates that 

 the dark area had a deterrent effect on the ameba 551. A food 

 cup was however soon formed and the globulin ingested. 



CONCLUSIONS. 



From these experiments it may be concluded that white light 

 and all the visible spectral colors cause positive responses; but 

 whether all are equally attractive cannot be definitely stated, 

 for experiments would have to be staged differently to produce 

 accurate results. Nevertheless the red end of the spectrum seems 

 to be somewhat more attractive than the blue. 



