18 MOTION. 



The muscles are always slightly stretched, as shown by 

 the fact that when a cut is made into a muscle the wound 

 gaps open ; the tension of the muscle is further shown by the 

 fact that when a bone is broken, as in the upper arm or thigh, 

 the ends of the bones slip by each other, and the limb has to 

 be strongly stretched to bring the ends back together. Mus- 

 cles act better when slightly stretched, and probably need a 

 slight resistant action of the opponent muscle. 



Symmetrical Development of the Muscles. The 

 muscles of the two sides of the body are the same in number 

 and arrangement. At birth they are probably about equal in 

 size, weight, and strength. Most persons early become right- 

 handed, and the greater use of the right hand and shoulder 

 makes the muscles of this side larger and heavier. The mus- 

 cles pulling on the bones slightly modify them in shape. The 

 whole body may become noticeably unsymmetrical. Most per- 

 sons step harder on one foot than on the other, as shown by 

 the sound of the footstep, and as shown by the constant wear- 

 ing of one shoe sole or heel faster than the other. This is 

 often caused by a tight shoe, or a peg in the sole, or other 

 irregularity, that for the time made it .painful or uncomfort- 

 able to bear the whole weight on that foot. So the habit may 

 be formed for life. The shoes of children should be carefully 

 examined. Better throw away a pair of shoes than make a 

 limper for life. The majority of persons limp, though not 

 lame. 



In very many persons one shoulder is habitually carried 

 higher than the other. Symmetrical development should be 

 carefully sought, and any tendency to a one-sided development 

 should, so far as possible, be avoided. 



We should use the left hand more. It should not be so 

 often " left." Surgeons and barbers are usually ambidextrous. 

 Probably it would not pay to try to do everything equally 



