io8 HUMAN PHYSIOLOGY CHAP. 



to cheapen the expense of living and to contribute to 

 health and happiness by presenting the foods in a 

 pleasing, palatable, and digestible form, so as to stimu- 

 late the appetite and aid the digestive processes. Cook- 

 ing is an art that can be mastered only by careful study 

 and intelligent, persistent practice. Every young woman 

 should regard it a rare accomplishment to be able to 

 cook and serve foods so that they will be of the greatest 

 nutritive value. 



86. Care of Teeth. Most persons do not sufficiently 

 realize the value of the teeth as organs of digestion. 

 It is a fact that many cases of indigestion and nervous- 

 ness arise from insufficient mastication because of poor 

 teeth. Our teeth must be kept in condition for daily use. 

 A tooth that has a cavity should be filled if it is worth 

 saving, and if not, it should be removed. If several teeth 

 are wanting, they should be replaced by artificial teeth. 



Bacteria are the chief cause of bad teeth. Many 

 harmless bacteria are found in the mouth, but others 

 produce poisonous substances that cause the teeth to 

 decay. Of course there are other minor causes that 

 tend to destroy the teeth, as taking into the mouth iron, 

 acids, etc., biting too hard substances, scratching, or in 

 any way injuring the enamel. 



Particles of foods lodge between the teeth and unless 

 removed at once afford excellent food material for bac- 

 teria. These little organisms attack the teeth and form 

 cavities in them. The discolored tartar so often seen 

 on teeth is due to the action of bacteria. The remedy 

 is difficult and expensive, but prevention in most cases 



