MANUAL OF NATURE STUDY. 
25 
food that a boy will eat? Will a horse? Why? 
Will a horse leave his oats to drink cold water, or 
hot coffee or tea? Will a boy? Will a dog eat hot 
potatoes and hot biscuits, and take a drink of cold 
water to cool the burning mouth and stomach ? 
Will a boy do that way ? Will a cat or dog leave 
between his or her teeth particles of food to rot and 
smell bad? Will some boys do that way ? Do cats 
and dogs have toothache ? Do boys ? Grown up 
boys ? 
Conclusion to be reached : 
1. Teeth are used for biting and chewing food. 
2. Sudden changes of temperature crack the 
enamel and thus cause decay. 
3. The use of tobacco is an injury to the teeth. 
4. Decaying particles of food generate an acid 
that causes the teeth to decay. 
5. The teeth must be thoroughly cleansed after 
each meal and immediately before retiring at night. 
6. In cleaning teeth a good tooth brush, or flan¬ 
nel cloth, with clean water of same temperature 
of mouth, should be used. 
4.—Lessons on the Bony Framework of the 
Body. 
Introduce this subject by a lesson on the umbrella, 
and let the children discuss freely the use of the 
stays and ribs. As analagous topics, the children 
