MANUA.I, OF NATURB STUDY. 61 



Then require the school to take vigorous exercise 

 of some sort, and take records again. 



Why does the circulation increase in rapidity ? 

 Why the increase in breathing ? 



To supply this waste requires food. Foods are 

 of four kinds, viz.: The albuminoids, starch and 

 sugar foods, fats, and mineral foods. 



Bread, milk,beans, peas, fish, lean meat and eggs 

 are regarded as strength-producing foods. These 

 are called albuminoids, because they contain 

 albumen, a substance closely resembling the white 

 of an egg. 



The starches are found in bread, oatmeal, pota- 

 toes, beans, corn and wheat in any form, fruits, 

 rice. 



The heat-producing foods are fats from animals, 

 and oils obtained from nuts. By eating nuts, but- 

 ter on our bread, fat pork or beef, we keep up the 

 heat of the body. In cold countries, like Klon- 

 dike, it is necessary to eat a great deal of fat. The 

 natives eat the fat of walruses and seals. 



What would the natives of Cuba or the Philip- 

 pines eat ? Would they have any use for walruses 

 or whale blubber ? Why ? 



All meats are valuable as food. Pork is hardest 

 to digest. It also contains a large amount of fat. 

 Then would it be good food for a hot or cold 



