8 GENERAL SCIENCE 



foods which have a tendency to cause constipation be- 

 cause of lack in bulk. Fruits and vegetables generally, 

 together with graham flour, corn bread, bran foods, and 

 oatmeal, are likely to stimulate the bowels to a normal 

 activity. 



The enamel of the teeth is the hardest substance in the 

 body. It contains no blood vessels, and when once cracked 

 or broken is not restored by nature. The dense bony mate- 

 rial beneath it, forming the body of the tooth and known as 

 dentine, decays when exposed to the action of bacteria. 

 Protection of the teeth from decay, and their preservation 

 throughout life, necessitates continuous care. Frequent 

 examination by a competent dentist is usually advisable, 

 especially during childhood and youth. It is better to pre- 

 vent decay than to be forced to repair its ravages. There 

 is no satisfactory substitute for a frequent use of the tooth- 

 brush. As the first of the thirty-two teeth in the permanent 

 set may grow into place when children are but six or seven 

 years of age, the habitual use of the brush should begin in 

 early childhood. 



It is often possible to tell much of a person's state of mind 

 from the expression of the lips and the mouth. The passing 

 emotions of mirth, scorn, or disgust are reflected in one's 

 face. Discontent, brutality, and vulgarity on the one hand, 

 or contentment and sweetness of disposition on the other, 

 stamp themselves indelibly upon the face. Repeated im- 

 pulses in the nerves distributed to the muscles of the face 

 leave their evidences of firmness or fickleness of purpose, 

 strength of character or weakness, in permanent lines formed 

 about the mouth. The kind of feelings cherished, and the 

 manner of thoughts indulged, sooner or later make or mar 

 one's expression. 



By means of the nerves the varied movements of the 

 numerous muscles of the body are directed and controlled. 



