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BOTANICAL GAZETTE 



usually a pseudopodium was sent upward from the upper surface of 

 the body. This pseudopodium was often seen to flatten out 

 against the cover slip. The nucleus moved up into the upper part 

 of this pseudopodium. In some cases so much of the protoplasm 

 flowed up into the pseudopodium that the amoeba became top- 

 heavy and toppled over. One amoeba was seen to send up a pseu- 

 dopodium, to fall over, and then to repeat the process three times 

 before it was killed. These reactions are really negative photo- 

 tropic responses, the amoeba moving upward away from the light. 



As the protoplasm flowed up into the vertical pseudopodium a 

 thick hyaline ectoplasm was left below. The ectoplasm usually 

 constituted the greater part of the lower half of the amoeba. Often 

 the amount of ectoplasm increased until it nearly equaled the 

 amount of endoplasm. In one case the cover glass was pressed 

 down on an amoeba while in this condition, and the endoplasm and 

 the ectoplasm separated and rounded up into separate drops. 

 Under a magnification of 2200 diameters the ectoplasm showed a few 

 small granules in Brownian motion, but showed no vacuoles. After 

 a prolonged exposure there was often a peculiar flowing of the 

 granular endoplasm out into the ectoplasm. It did not appear to 

 be the same kind of motion that one observes in the regular stream- 

 ing of the protoplasm, but it was not easy to say wherein the differ- 

 ence lay. After this all motion ceased and the protoplasm appeared 

 coagulated. Under a high magnification (2200 diameters) the pro- 

 toplasm was seen to be filled with fine vacuoles which were so 

 numerous that it was converted into a fine froth. These vacuoles 

 were not visible before the organism was exposed to the light. 



It often happened that only a part of an amoeba was killed; for 

 example, in one case an amoeba which happened to be near a bit 

 of opaque substance when the exposure was made sent a pseudo- 

 podium up on top of the opaque substance. The nucleus was next 

 sent up, and then as much of the granular protoplasm as possible. 

 The bit was not large enough to protect the whole organism, and a 

 fringe of protoplasm (ectoplasm) extended beyond it all the way 

 around. The exposure was continued until this fringe was killed. 

 After the exposure, the unexposed part of the organism moved 

 away, leaving the dead fringe behind. In another case the light 



