INFLUENCE OF NUCLEUS ON BEHAVIOR OF AMCEBA. 255 



Verworn (1909) agrees with Hofer in holding that there is a 

 difference in the behavior of parts of Amoeba with and parts 

 without a nucleus, but does not agree with him in the conclusion 

 that the nucleus exerts a direct influence on the movement; 

 that is, he does not think that the nucleus is a regulatory 

 "centrum" for movement. 



Judging from the results of my experiments, it is clear that 

 there are distinct differences in the behavior of parts of Amoeba 

 which contain and parts which do not contain a nucleus. Dif- 

 ferences in such parts have been observed in the character of 

 movement, in the accuracy of orientation in light and in the 

 rate of locomotion. It is clear, also, that these differences are 

 traceable to the nucleus. 



FIG. i. Camera sketches showing changes in form and the characteristic 

 movements in the nucleated and enucleated parts of an amoeba immediately 

 after being cut in two. The arrows indicate the direction of movement. 1-3, 

 enucleated part; ak, nucleated part; mm, projected scale. The sketches of the 

 enucleated part were made at five-minute intervals; those of the nucleated part 

 at one minute intervals. Note that the nucleated part progressed regularly in a 

 given direction, and that the enucleated part changed its form and position only 

 slightly. 



MATERIAL AND METHODS. 



The specimens used for the most part in this w T ork appeared 

 in a battery jar containing an old paramecium culture. They 

 corresponded to descriptions of Amceba proteus and were rather 

 sensitive to light. Nucleated and enucleated parts were ob- 

 tained by cutting specimens in two with finely drawn glass rods. 



