FOODS AND NUTRITION 387 



are attractive advertisements of " breakfast foods, " 

 prepared meats, and various other foods. Of course 

 these foods cost more than food in the bulk; but their 

 increased use from year to year indicates that people 

 are willing to pay more in the interest of food hygiene 

 and their own convenience. These manufactured foods 

 are perhaps slowly changing our eating habits. Break- 

 fast is becoming a meal of fruits and cereals instead of 

 the heavy meal of fifty years ago. Bread making in 



FIG. 345. Development of the Locomotive. 



some localities is already a factory problem, and with 

 better methods of manufacture and distribution the use 

 of baker's bread is certain to increase. 



Nature's Food Factories. Man's food must contain 

 whatever is needed to build and repair the body, to give 

 it fuel for heat and to regulate certain processes of the 

 body. Plants derive their nourishment largely from the 

 mineral kingdom, and animals derive their nourishment 

 from plants and animals that feed upon plants. It is 

 true that animals require certain inorganic materials such 

 as water and salt, but the sources of real foods are plants 



