6 CELL INTELLIGENCE THE CAUSE OF EVOLUTION 



them have "mouths" ; others simply take their food in at 

 any part of the body by allowing their protoplasm to 

 flow around it. Some of them have organs for locomo- 

 tion, others do not ; some have shells, while others have 

 no covering at all. But each is a single cell and each 

 carries out its own life process, such as respiration, secre- 

 tion, multiplication, etc. The cell cannot be subdivided 

 into smaller units which would be able to sustain inde- 

 pendent life 



"Sinc.e such cells are the simplest parts into which 

 living matter can be divided, we may call them "Units 

 of Life" and may regard our bodies as a combination of 

 a large number of such units, considering the life of the 

 whole body as the sum of the lives of its different cells. 

 We should constantly remember that it is really the cells 

 which are the active living parts. The combined lives of 

 all these millions of cells make the life of the whole, 

 much as the combined lives of the persons within a city 

 make up its life. 



"As we have seen, some animals are composed of a 

 single cell. But this cell is able to carry on all the func- 

 tions of life : it feeds, digests, respires, moves, multiplies 

 and performs all the necessary duties of complete, in- 

 dividual life. In our own bodies there are many cells, 

 but each is not capable of carrying on all the functions of 

 life and if separated from the others, would die. Each is 

 able to do primarily only one thing, hence, each is de- 

 pendent upon the others. 



"It may be asked, why we should have so many kinds 

 of cells in our bodies and why with us too, one kind of 

 cell could not serve all purposes. The answer is easy to 

 give. A hermit can himself do everything needful to 

 support his life : he can prepare his own food, make his 

 own clothes and build his own shelter, but he can do this 



