94 



OUR FOOD SUPPLY 



digestive juices than are larger pieces. It is essential, 

 therefore, that a clean mouth and sound teeth be 

 maintained. 



Proper diet is an important factor in building up 

 and maintaining sound teeth. The enamel, the hard, 

 outer structure of teeth, is formed largely from cal- 

 cium and phosphorus. Certain vitamins, especially 

 vitamin D, must be present in our diet, in order that 

 the body can utilize minerals in building teeth. If 

 liberal amounts of fruit, leafy vegetables, and milk 

 are included in the daily diet and if our bodies receive 

 a reasonable amount of exposure to sunshine, all the 

 essential elements for the building of sound teeth will 

 be provided. 



Teeth are subject to decay, but they do not repair 

 themselves. Every person should visit a dentist at 



Capillaries 



a/Head, 

 Chest,and urns 



Capillaries 

 of Lungs 



Capillaries 

 of Stomach 

 Intestines, 

 and Spleen 



Capillaries 

 of Legs 



FIG. 135. CIRCULATORY SYSTEM OF MAN 



least once a year. The mouth should be inspected for 

 the beginning of tooth cavities and diseases of the 

 gums. The teeth should be cleaned and repaired if 

 necessary. It is poor economy to delay having the 

 teeth repaired until they are badly damaged. One 

 should not bite hard objects with the teeth. Cracking 

 nuts, biting very hard candy, or biting string may 

 crack the enamel. Pins and needles should not be 

 used to pick the teeth. Why? 



The following factors may influence digestion : 



Poor posture, which cramps the digestive organs and 

 which may prevent good circulation of blood through 

 them. 



Fatigue. Undue fatigue may prevent satisfactory di- 

 gestion. When "too tired to eat," rest a while before 

 eating a full meal. 



Lack of exercise is one of the causes of a poor appe- 

 tite. Lack of exercise may also result in poor circu- 

 lation. Daily moderate exercise tends to stimulate the 

 appetite and also to "tone up" the digestive system. 



It is not considered wise, however to indulge in stren- 

 uous exercise immediately after a heavy meal. 



Emotional state. Pleasant emotions increase the appe- 

 tite and aid the flow of digestive juices. Worry, anger, 

 and fear retard the digestive processes and in extreme 

 cases may even cause digestion to cease. One should 

 form the habit of being cheerful at meal time. Avoid 

 quarreling and talking over your troubles while eat- 

 ing. Make breakfast, lunch, and dinner happy occa- 

 sions. 



Constipation. Improper eating may cause constipation. 

 Usually waste matter is eliminated from the intestines 

 once every twenty-four hours. If waste materials are 

 held in the body too long, they may irritate the in- 

 testinal tract and cause pain and symptoms of in- 

 digestion. Constipation may also produce headache 

 or make one feel sluggish and drowsy. 



Medicines are available for the relief of constipation, 

 but it is better to aid the bowels to do their work 

 themselves. The following things are suggested to 

 accomplish this purpose. Daily outdoor exercise 

 seems to increase the vitality of all the cells. Exercises 

 which strengthen the abdominal muscles are helpful. 



air 



Windpipe 



(Zrtery carrying 

 blood from heart 

 to lungs 



Veins carrying 

 blood from lungs 

 to heart 



Heart 



FIG. 136. LUNG OF MAN 



Persons who have poor posture and weak abdominal 

 muscles which result in sagging intestines frequently 

 suffer from constipation. Drinking more water, es- 

 pecially before retiring at night and after arising in 

 the morning, and eating more fruit, vegetables, and 

 coarse foods such as bran muffins and bran bread 

 which supply plenty of roughage bring relief in most 

 cases. In case of persistent constipation it is best to 

 consult a physician. 



