THE HYGIENE OF NUTRITION 363 



time it should not be rinsed out but left in the by-places 

 of the mouth to guard against the development of an 

 acid reaction. The brushing of the teeth may be over- 

 done; it should cleanse their surfaces but should not 

 be so directed as to encourage recession of the gums. 

 It is often assumed that people with poor teeth are pay- 

 ing the penalty for their neglect. Sometimes, of course, 

 this is a fact, but it is also true that many people have 

 superb teeth which they owe entirely to good fortune 

 and not to conscientious care. 



The assistance of the dentist must be had at short 

 intervals by many subjects. Teeth which are in need 

 of filling or other treatment are most detrimental. They 

 are not merely disfiguring and responsible for bad breath, 

 but their presence deters the possessor from using proper 

 force in mastication. It is believed in addition that 

 defective teeth are often foci from which most injurious 

 infections are spread to other parts of the system. The 

 ugly fact stands out that our teeth, being incapable of 

 self-repair, force upon us an early reminder of our 

 mortality. 



