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S. O. MAST 
Fig. 1 Sketches representing the reactions of an amoeba proceeding toward an 
intense area of light the rays of which were perpendicular to the slide. L, field of 
light formed by focusing a limited section of i Welsbach mantle on the slide. I-IO, 
successive positions of an amoeba a little less than one-half minute apart. 
Arrows indicate direction of streaming in pseudopods. 
