INDIVIDUAL VEGETABLE CELLS. 27 



OHAPTEE Y. 



INDIVIDUAL VEGETABLE CELLS. 



1. THE elementary masses of bioplasm (Sec. 2, Chap. 

 II) are usually called cells, even if they are merely 

 pieces of animated jelly, uninclosed by an outside 

 shell or membrane. Some of these cells remain un- 

 connected with others during their entire life, and 

 multiply by self-division. Others have a living or 

 vital connection with neighboring cells, so as to form 

 tissues and organs. In this chapter we shall consider 

 the vegetable cell as an individual its various ap- 

 pearances and its activities. 



2. It is not easy to distinguish between the cell, or 

 living matter, of an animal and a vegetable. Some 

 cells appear like animals at one part of their lives and 

 like vegetables at another part. After long study 

 learned naturalists have agreed that the principal dif- 

 ference between animals and plants is that the latter 

 can be nourished by simple mineral or chemical (that 

 is, unorganized) matter, while animal nutrition re- 

 quires material which has been organized, or made 

 part of a living being. 



3. Most vegetable cells produce a membrane, or cett- 

 watt, on the outside, within which the living matter 



