BIOLOGY AND HEALTH 437 



The exercise of the abdominal muscles is the most important 

 in order to give tone to those muscles and thus aid the portal cir- 

 culation. For the same reason erect posture, not only in standing, 

 but in sitting, is important. Support the hollow of the back by a 

 cushion or otherwise. 



Exercise should always be limited by fatigue, which brings with 

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

 use of diet and air is proper, the fatigue point will be much further 

 off than otherwise. 



One should learn to relax when not in activity. The habit pro- 

 duces rest, even between exertions very close together, and enables 

 one to continue to repeat those exertions for a much longer time 

 than otherwise. The habit of lying down when tired is a good one. 



The same principles apply to mental rest. Avoid worry, anger, 

 fear, excitement, hate, jealousy, grief, and all depressing or ab- 

 normal mental states. This is to be done not so much by repressing 

 these feelings as by dropping or ignoring them that is, by divert- 

 ing and controlling the attention. The secret of mental hygiene 

 lies in the direction of attention. One's mental attitude, from a 

 hygienic standpoint, ought to be optimistic and serene, and this 

 attitude should be striven for not only in order to produce health, 

 but as an end in itself, for which, in fact, even health is properly 

 sought. In addition, the individual should, of course, avoid in- 

 fection, poisons, and other dangers. 



Occasional physical examination by a competent medical ex- 

 aminer is advisable. In case of illness, competent medical treat- 

 ment should be sought. 



Finally, the duty of the individual does not end with personal 

 hygiene. He should take part in the movements to secure better 

 public hygiene in city, state, and nation. He has a selfish as well 

 as an altruistic motive to do this. His air, water, and food depend 

 on health legislation and administration. 



COLLATERAL READING 



School Hygiene, Shaw, entire; Outlines of Practical Sanitation, Bashore, 

 see index; The Health of the City, Godfrey, see index; Handbook of Health, 



