ities of the cell, the disagreement is, in some cases, 

 readily understood. The phenomena of movein^ent, being the 

 ones most readily observed, have been studied most extens- 

 ively. Nussbaum observed that in the enucleated pieces of 

 infusoria the cilia continued to beat up to the onset of 

 death. In like manner Balbiani and verworn observed that 

 the normal activity of the cilia continued after the nu- 

 cleus had been removed, until death changes set in. '.Vith 

 regard to ameboid movement, however, there is some differ- 

 tnce of opinion. Gruber observed that enucleated pieces 

 of Araeba proteus ceased making normal movements soon after 

 the operation, and this was confirmed by Hofer (IRPO) and 

 by Willis (ioiG). 3tolc (iQiO) however, apparently using 

 a different variety of Ameba proteus, observed normal 

 movements for days after removal of the nucleus. But the 

 most striking experiments upon the influence of the nu- 

 cleus upon normal movement were made by Verworn, using 

 Liacrymaria olor, in which the movements are very complex. 

 This flask-shaped ciliate extends its long neck and waves 

 it about, the cilia upon the head end beating actively, 

 and then suddenly retracts like an elastic band, to re- 

 peat the performance later. If stimulated it swims away. 

 Non-nucleated parts of this organism, regardless of which 

 part is selected, exhibit the same characteristic -ind 



(12) 



