A STUDY OF LIVING SUBSTANCE 



31 



the end of the process the " mother cell " has been equally 

 divided into two " daughter cells," each having a nucleus 

 and cell body. The daughter cells now move about, take 

 in food, grow, and in turn divide. The amoeba " family " 

 now consists of four " granddaughter cells.' 7 



The process of cell division in many of the human tis- 



FIG. 10. An Amoeba in Successive Stages of Division. 

 The dark spot is the nucleus. The light spot is the contractile vacuole. 



sues is far more complicated than in the amoeba. The 

 essential facts are true, however, in almost every case of 

 cell division. They are these : (1) the material of the 

 mother nucleus is divided in such a way that each daughter 

 cell receives exactly one half; (2) a more or less equal 

 division of the material of tne cell body follows j (3) this 



