20 BOTANY OF THE LIVING PLANT 



I. II. III. 



A 



IV. 



VI. 



IX. 



VIII. 



VII. 



Fig. II. 

 I. -IX. Successive stages, drawn from different individual cells of the same root 

 of Allium cepahyDv.]. M.Thompson ( x 730). They illustrate the steps in the pro- 

 cess of division of a vegetative cell . Such division accounts for the normal increase in 

 number of cells in the " soma," or plant-body : it is therefore called somatic division. 

 Details of behaviour of the nucleus in division will be given later (Chapter xxxi.). 



The division of the cell being constantly as described, it follows 

 that every cell arises from a pre-existent cell, and every nucleus is 

 derived from a pre-existent nucleus, by division. The plastids also 



