120 DIGESTION 



Human teeth partake of both, forms ; some of- them are sharp, 

 and others are blunt ; they are therefore well adapted for the 

 mastication of both flesh and vegetables. Hence we infer 

 that, although man may live exclusively upon either vegetable 

 or animal food, he should, when possible, choose a diet made 

 up of both varieties. 



11. Preservation of the Teeth. In order that the teeth shall 

 remain in a sound and serviceable condition, some care is of 

 course requisite. In the first place, they require frequent 

 cleansing; for every time we take food, some particles of it 

 remain in the mouth, and these, on account of the heat and 

 moisture present, soon begin to putrefy. This not only ren- 

 ders the breath very offensive, but promotes decay of the teeth. 



12. The saliva, or moisture of the mouth, undergoes a 

 putrefactive change, and becomes the fertile soil in which a 

 certain minute fungus has its growth. This fluid, too, if 

 allowed to dry in the mouth, collects upon the^teeth in the 

 form of an unsightly, yellow concretion, called tartar. To 

 prevent this formation, and to remove other offensive sub- 

 stances, the teeth should be frequently cleaned with water, 

 applied by means of a soft tooth-brush. The prevention of 

 the tartar fungus is best effected by the use of a weak solution 

 of carbolic acid. {Bead Note 1.) 



1. The Proper Care of the Teeth. "In the famous history of Don 

 Quixote, the hero of La Mancha, it is related that at the end of one of 

 his great battles, wherein he was as usual conquered, he found himself 

 wounded in the face by a violent blow from a stone, and grieved to find 

 that with it he had lost one of his teeth. Reflecting awhile on this un- 

 happy accident, he sagely remarked that to lose a molar was very much 

 like losing an old friend. And it is an important question, in view of 

 this bit of wisdom, how to care for the molars, that they may become old 

 friends. To this end, the cardinal maxim is cleanliness ; and again clean- 

 liness. One means of cleansing is the natural one that is, by chewing 

 food ; for it is well known that if we have a tooth so situated in the jaw 

 that it is seldom brought into use, that tooth early shows signs of decay. 

 But more effectual is the artificial means the brush. Children should 

 early be taught to use this ; and for them a softer brush should be selected 



11. Cleaning of teeth ? Effects of not cleaning ? 



12. Effects of the saliva ? Formation of tartar ? How prevented ? How destroyed ? 



