. BONES, MUSCLES, EXERCISE, AND REST. 295 



681. The state of the digestive organs should be regarded 

 when we exercise. We should not work just before eating, 

 especially if we have long fasted and are hungry, for then 

 the system is comparatively weak, and needs nourishment, 

 and is therefore easily exhausted by exertion. And more- 

 over, muscular action would expend the nervous energies 

 that should be reserved to sustain the stomach in digesting 

 the coming meal. ( 104, p. 77.) Neither should we exercise 

 immediately after eating, for the. work of digestion requires 

 all the energies of the system, until the food becomes thor- 

 oughly mixed with the gastric juice. 



CHAPTER XIII. 



Place for Exercise. Should not be in House, but in open Air. 

 Exercise should be frequent and regular. All need it, especially 

 the Sedentary. Consequences of Neglect. 



682. WE need an abundant supply of oxygen to sustain 

 the increased demand for nutrition and discharge of waste 

 which is caused by muscular action. Exercise abroad in the 

 open air gives more health and vigoi to both body and mind 

 than exercise in the house. Some have prepared gymnastic 

 apparatus in their garrets, or in their cellars, in order that 

 they and their families may exercise without the trouble and 

 exposure of going out of doors. Some gentlemen in cities 

 saw and split wood in their cellars ; but they fail of obtaining 

 the full measure of good that action in open air would 

 give them. Even those mechanics whose employments give 

 them sufficiency of muscular exercise, especially those who 

 work in close shops, would do well to add a walk abroad to 

 their in-door labors; for they would gain in vigor of body, and 

 freshness of spirit, and effective power, more than sufficient 

 to compensate for the loss of time devoted to their renovation. 



683. Whatever may be the weather or the season, the 

 demand of the system for exercise abroad is the same; for 



