CELL DIVISION 269 



and cytoplasm. In the division of the cell, equal numbers 

 of these chromosomes are found at its equator. Half of these 

 chromosomes then go to the opposite poles of the cell and 

 unite again to form at each pole a nucleus. A cell-wall is 

 then laid down at the equator, and we have two cells in the 

 place of one. Enlargement and further changes may go on 

 in these two cells. The method of cell division by this complex 

 means is known as mitosis or karyokinesis. It is exceedingly 

 complex and too difficult for the beginner to follow or to 

 comprehend. Some of the stages are given in Fig. 442. A 

 more detailed representation of these changes is shown in 

 Fig. 443. 



Review. — Of what is the plant composed? What is the general 

 nature of cells? Forms of cells? What part of the cell is dead matter? 

 Living matter? Compare different cells studied. State your conception 

 of protoplasm. State the divisions in the protoplasm. Name two kinds 

 of movement of protoplasm. What is the nature of the cell- wall? Its 

 modifications? How do cells multiply? 



