PHYSIOLOGY FOR BEGINNERS 



complex substances which plants form, and which are spoken 

 of as organic. Animals can live only on plants or on the sub- 

 stances of which other animals consist, substances which have 

 themselves been formed from plants. 



Animals are able to do freely what plants rarely do, or 

 do to a slight degree only. An animal can move ; either the 

 animal can move its body from place to place, or, if fixed, can 

 move some of its parts relatively to its other parts. Moreover, 

 it can apparently move of its own accord. It is said to be 

 automatic. Again, an animal responds to influences exerted 

 on it. If it is disturbed it will move, or if it is interfered with 

 when it is moving, it will stop moving, or move faster, or move 

 in some different way. These are familiar properties of animals, 

 but are only rarely seen in plants. 





