328 THE POPULAR SCIENCE MONTHLY. 



them. So, too, in walking, how few use the muscles of the calf of 

 the leg ? Most people merely stamp along the path or road. They 

 do not use the foot from heel to toe. They fail to rise on the toes at 

 the end of the step, and do not push themselves along with those im- 

 portant members of the foot. Thus they lose the best part of the 

 leverage of that important muscle or set of muscles of the lower leg. 

 The fault is frequently in the shoe of the walker. That has too high 

 a heel, and pinches the toes, making any movement of them painful, 

 even if it does not prevent them from moving at all. 



By making regular daily use of the muscles of all the muscles, if 

 that were possible we should do one thing toward establishing per- 

 fect health of body by allowing to one very large part of it a fair 

 chance to appropriate its proper elements from the blood, and oppor- 

 tunity to give back its used-up tissue to be eliminated from the sys- 

 tem in natural and healthy ways. We should be doing more than 

 simply repairing the muscles. We should be also evolving heat a 

 very important factor of life. We should be assisting all the other 

 parts of our organization to do their work. 



Take the heart itself a very bundle of muscular fibers. We know 

 that as long as we live, whether sleeping or waking, that wonderful 

 organ keeps up its regular contractions and expansions. But, when 

 we use our muscles, their contractile force upon the blood-vessels helps 

 the blood along its channels, and thus takes a little labor from the 

 propelling heart. It beats faster but with less effort. 



While helping the heart, muscular exercise helps the lungs also. 

 More exercise means for the lungs more breath ; that is, more air in- 

 spired, and more carbonic-acid gas expired. By deeper breathings the 

 involuntary muscles are strengthened. Moreover, we are made to feel 

 the need of greater lung-room. Even after the age when full stature 

 is supposed to be attained, that lung-room often comes, Nature furnish- 

 ing the supply according to the demand. McLaren notes the case of 

 one man, in his thirty-sixth year, whose chest, under systematic exer- 

 cise, increased in girth from thirty-two to thirty-six and a half inches 

 in two months. There was an addition of four and a half inches to the 

 circumference of the chest. " An addition of three inches to circum- 

 ference of chest implies that the lungs, instead of containing 250 cubic 

 inches of air before their functional activity was exalted, are now 

 capable of receiving 300 cubic inches into their cells." * This great in- 

 crease, of four and a half inches, meant not only increase of lung- 

 room, but increase of lung-power. 



Taking the quantity of air inspired in the reclining position in a given time as the 



unit 1 



In the same period of time the quantity of air inspired when standing is . . 133 



When walking one mile per hour, is 1*9 



"When walking four miles per hour, is 5 



When riding and trotting, is 405 



When swimming, is 4-33 f 



* " University Oars," Dr. Morgan. f " Health," Dr. Edward Smith. 



