CELLS I I 



starch changes to sugar. When starch is eaten, it is also 

 changed to sugar. So starch and sugar are the same kind 

 of food. About one 

 quarter of a pound of 

 starch or sugar must 

 be eaten each day. 



8. Minerals. In 

 the body there are also 

 minerals, such as lime, 



iron, potash, and salt. starch grains (x 400). 



When the body is lr a, of potato. b, of corn, 



burned, these are left 



behind as ashes. The lime stiffens the bones. Iron is 

 found in the blood and coloring matter of the body. 

 Potash and salt are found all through the body. These 

 minerals are found in all food, for all leave ashes when 

 burned. Yet some salt must be added to food. 



9. Food. Everything which makes the cells and fluids 

 of the body is composed of either water, albumin, fat, 

 sugar, or minerals. These sustain life, and are, foods. All 

 other kinds of substances are harmful or poisonous. 



10. Oxidation. All kinds of food are constantly being 

 eaten, and yet only water and mineral substances leave 

 the body in anything like the form in which they entered. 

 What becomes of the rest ? 



When a piece of meat is put into a hot fire, it bursts 

 into a flame and burns to smoke and ashes. By its burn- 

 ing it gives off heat, and makes the fire hotter. If the 

 draft of the stove is closed tightly, the fire does not burn, 

 for a stream of air must flow steadily into the fire. The 

 air is one fifth oxygen gas. This oxygen unites with the 

 meat and forms two invisible gases carbonic acid gas 

 and vapor of water. These gases are the smoke. The 



