ISO RESPIRA^riON AND EXCRETION 



Change of Air. — Persons in poor health, especially those having 

 tuberculosis, are often said to be cured by '^ a change of air." This 

 is probably not so much due to the composition of the air as to 

 change of occupation, rest, and good food. Mountain air is dry 

 and relativel.y free from dust and bacteria, and often helps a person 

 having tuberculosis. Air at the seaside is beneficial for some forms 

 of disease, especialh^ hay fever and bone tuberculosis. Many 

 sanitariums for this latter disease have been established near the 

 ocean, and they have assisted in saving thousands of lives. 



Relation of Proper Exercise to Health. — We are all aware that 

 exercise in moderation has a beneficial effect upon the human or- 

 ganism. The pale face, drooping shoulders, and narrow chest of 

 the boy or girl who takes no regular exercise are too well known. 

 Exercise, besides training the muscles, increases the activity of 

 the heart and lungs, causing deeper breathing and giving the 

 heart muscles increased work; it liberates heat and carbon 

 dioxide from the tissues where the work is taking jDlace, thus in- 

 creasing the respiration of the tissues themselves, and aids me- 

 chanicalh^ in the removal of wastes from tissues. It is well know^n 

 that exercise, when taken some little time after eating, has a very 

 beneficial effect upon digestion. Exercise and especially games 

 are of immense importance to the nervous system as a means of 

 rest. The number of playgrounds in this country is increasing, 

 because of this acknowledged need of exercise, especially for grow- 

 ing children. 



Proper exercise should be moderate and varied. Walking in 

 itself is a valuable means of exercising certain muscles, and so is 

 swimming, but neither is ideal as the only form to be used. Vary 

 your exercise so as to bring different muscles into play, take exer- 

 cise that will allow free breathing out of doors if possible, and the 

 natural fatigue which follows will lead you to take the rest and sleep 

 that every normal body requires. 



Exercise should always be limited by fatigue, which brings with 

 it fatigue poisons. This is nature's signal to rest. If one eats 

 proper food and breathes fresh air, the fatigue point will be much 

 further off than otherwise. One should learn to relax when not 

 in activity. Even a small amount of rest, between exertions 

 which are very close together, increases greatly the length of time 



