THE BEGINNINGS OF LIFE. 475 



quently undergo the most startling series of develop- 

 mental transformations. 



In order to watch these changes, all that is necessary, 

 according to M. Nicolet, is to prepare one of the inter- 

 nodes of Chara in the following manner : Having 

 stripped off the peripheral cells which form a kind of 

 sheath for the central compartment, a fine thread is to 

 be tied pretty tightly around each end, just within the 

 node ; the nodes themselves should then be cut off, and, 

 after all foreign material has been removed from its 

 surface by means of a soft brush, the portion of the 

 internode between the two ligatures should be immersed 

 in a vessel of very pure water and maintained there in 

 a more or less vertical position. Thus prepared, the cell 

 ought to be quite transparent, and, when examined with 

 the microscope, the circulation of the cell contents 

 should be easily observable. This circulation continues 

 for a variable time days, or even weeks according 

 to the degree of vitality of the plant to which it 

 formerly belonged. After a time, however, certain 

 other changes take place, which are thus described by 

 Nicolet : c In following the movements of the liquid, 

 it may soon be noticed that it deposits, at the inferior 

 extremity of the cell, a material which is more dense 

 and more glutinous than that of the liquid in move- 

 ment, and which soon begins to become rounded, 

 turning on its axis, on account of the impulsion it 

 receives from the movement of the fluid in which it is 

 immersed, though it remains in the same situation. . . . 



