232 



MENTAL HYGIENE 



kept healthy by fresh air, good 

 food, sleep, rest, sunlight, and 

 exercise. The nervous system 

 is probably more sensitive to 

 the lack of any one of these 

 conditions than any other sys- 

 tem in the body. A change of 

 activity is frequently bene- 

 ficial. Otherwise, , a person 

 may become physically as well 

 as mentally fatigued, thus 

 greatly reducing his efficiency. 

 Every person should have a 

 hobby and follow it as much as 



Idleness does not bring satisfaction for any possible. A hobby that takes 

 great length of time. It is, frequently, the result , . , 



of bad habits and usually, if not always, leads to him OUt OI doors IS more de- 



sirable than one that keeps 



him indoors. People with hobbies are usually able to make use 

 of their leisure time in a way that is enjoyable as well as bene- 

 ficial to them. 



Fatigue. Prolonged or continued contractions of muscles in 

 any kind of work result in fatigue. This condition is almost 

 always followed by a steady decrease in efficiency. The feeling of 

 fatigue is very complex and is often associated with such mental 

 states as lack of interest, lack of will power, and distaste for the 

 work. Work done under compulsion usually results in fatigue 

 more readily than when interest is a part of the work. This is one 

 reason why every one should do the kind of work which he really 

 likes. 



Experiments have shown that if some blood of a fatigued animal 

 is injected into a rested one, signs of fatigue are promptly produced 

 in the second animal. Fatigue is probably due to an accumula- 

 tion of waste substances in the cells and in the blood, resulting from 



