fashion, but the movement of the non-nucleated 

 piece h:"T.s become perceptibly sloviev. 

 5:28 P.i-i.- The non-nucleated piece ceases its progressive 

 moveiTients and slowly retracts into a somewhat 

 corrugated sphere. Only an occasional very 

 blunt pseudopod is now produced, and slight 

 a^^itation shows that the fragment is no longer 

 attached to the slide. The nucleated piece 



differs from a normal ameba only in size. 



* 



The retraction into the spherical shape is an invar- 

 iable phenomenon, and is of such a definite character that 

 the tine of its appearance nay be accurately determined. 

 Thus in 15 amebas which were so divided that the nucleus 

 remained in the posterior half, the retraction occurred 

 at an average of 9 minutes after the onrration. To the 

 observer it resembles strongly the response to stimulation, 

 except for the absence of the protoplasmic droplets mention- 

 ed above. The protoplasm is still capable of movement, as 

 is shown by transferring it to another medium, such as 

 distilled water, to which it responds by a change of shape. 



This effect of amputation of the nucleus upon move- 

 ment is not always permanent. If a number of amebas are 

 cut in half, and the nucleated and non-nucleated pieces 

 observed each day, on the first or second day after the 

 operation it will be noticed that many of the non-nucleated 

 fragments are moving in the typicxl limax fashion, and in 

 fact there is sometimes no great difference between the 



(27) 



