APPLIED PHYSIOLOGY 



Gardening and housework are also exercise, and should be 

 taught to every child. 



A bicycle affords good exercise. If a person does not 

 race or go on long rides, it will do him no harm. Even 

 old men and very small children can ride it safely. 



Gymnasiums are of great value in taking exercise. By 

 the use of dumb-bells and Indian clubs, and by lifting 

 light chest weights, any weak part of the body can be 

 made strong. The only trouble in the use of these is that 

 we soon get tired of one thing. In classes and under a 

 teacher they afford interesting and profitable exercise. 



338. The face muscles. The muscles of the face are 

 flat and fastened to the skin. When they act, they draw 



Illustration of the change of expression produced by the muscles 

 of the mouth. 



and pucker the skin in different directions. Each kind of 

 feeling in the mind causes the muscles to act in a certain 

 way. If we feel happy, the muscles draw the ends of the 

 mouth upward and backward. This makes a smile. If 

 we feel sad, the muscles draw the ends of the mouth 

 down. By looking at a person's face we can often tell 

 how he is feeling. 



339. Effects of alcohol and tobacco. Alcohol appro- 

 priates oxygen belonging to the muscle cells and prevents 

 the stomach and liver from preparing food for their use. 



