CHAP. L] THE CELL. 7 



with any foreign particle, the protoplasm, by virtue of its amo3- 

 boid movements, tends to flow round and enwrap the particles, 

 and particles thus enwrapped or incepted may then be conveyed 

 by the cell from one place to another. 



The nucleus. The nucleus of a cell is directly concerned in 

 the reproduction and division of the cells. In dividing, the 

 nucleus passes through a series of remarkable changes, which 

 are too complicated to be studied here. (See Fig. 3.) The 

 result of these changes is that either directly or indirectly the 

 nucleus splits into two, the protoplasm divides and arranges 

 itself around the new nuclei ; these daughter cells soon grow to 

 the size of the parent cell, and division of these and consequent 

 multiplication may proceed with great rapidity. 



To sum up: The cell assimilates, is continually building 

 itself up, and replenishing its store of energy, is as continually 

 breaking down into simpler products, with a setting free of 

 energy ; it grows ; it moves ; it reproduces itself in other 

 words, it is alive and is the basis of all life. 



