THIRD ANNUAL YEAR BOOK — PART X. 



611 



These results will be of value when we compare them with other pro- 

 ducts such as the breakfast foods, as for example: 



AMOUNTS OP NUTRIENTS FURNISHED FOR TEN CENTS IN CEREAL FOODS AT 



ORDINARY PRICES. 



2. Maine Exp. Sta. Bui. 83, p. 138. 



The results show that some of the common nuts furnish nutritive 

 material as reasonable in price as many of the well advertised breakfast 

 foods. The chestnut can no doubt be used in preparing special dishes 

 and its use extended in many ways. Attention should be not only given 

 to the production of the various varieties of nuts but we should learn how 

 to use them to the best advantage. 



The seed of the forest tree when pressed into the soil sends down 

 its rootlet to collect the plant food and moisture. At the same time it 

 sends up its tiny leaves to meet the sunlight. The plant food brought 

 up by the root is combined with the material taken from the air and the 

 tree grows. As the years go by the tree becomes larger, sends its roots 

 down deeper in the soil, and spreads its thousands of leaves to collect 

 the material from the atmosphere. The different varieties of trees each 

 have their characteristics which they have elaborated from the plant 

 food in a common soil and from a common atmosphere. The leaf of a tree 

 is a small part of nature's laboratory, taking from the invisible gases 

 what is needed for its purpose. The atmosphere is a mixture of gases 

 consisting of 



78.40 parts nitrogen. 

 20.94 " oxygen. 

 .63 " argon. 

 .03 " carbon dioxide. 



100.00 



The leaves of the tree take from the atmosphere the carbon dioxide 

 and with the water brought by the roots change it to products which 

 ultimately become part of the tree. In producing this change the carbon 

 dioxide is returned to the atmosphere. The mutual dependence of plant 

 and animals is seen in this relation, the animal using products of vege- 



