THE STORING PROCESS 



157 



sugar, which, in composition, is almost the same as 

 starch. 



107. The storing process is exceedingly interesting, and 

 the farmer ought to understand it. Starch is formed 

 mostly in the leaves. The sunlight and the green sub- 

 stance of the leaves 

 (chlorophyll) manufac- 

 ture it out of carbon di- 

 oxide and water. 1 The 

 rest of the process varies 

 in different plants. In 

 the potato plant the 

 starch is next turned 

 into sugar. The sap then 

 dissolves this sugar, 2 and 

 carries it to the under- 

 ground tubers, where it 

 is turned back into starch 



CHLOROPHYLL BODIES OF A LEAF. 



Note the separate cells, each containing 

 about half a dozen chlorophyll bodies. 



and stored away. In 

 some plants, during 

 these parts of the pro- 

 cess, deposits of sugar itself are formed. Other plants 

 form deposits of gums, which are always nearly like 

 starch and sugar in composition. Still other plants deposit 

 fatty substances that we call oils. Vegetable oils are 

 found especially in the olive, in cotton seed, and in nuts. 

 The coconut is an extreme instance of an oily food 

 deposit. Fats, like carbohydrates, furnish heat. 



1 In this part of the process, some oxygen is thrown off into the air as a 

 by-product. Plants breathe through fine pores usually on the under side 

 of their leaves, much as the higher animals breathe through their nostrils. 

 But animals take the air for the sake of its oxygen, and their lungs throw 

 off into the air carbon dioxide. Plants breathe largely to get this cavbon 

 dioxide, and throw off some oxygen. However, plants do consume some 

 oxygen, and in this respect they resemble animals. 



2 It cannot well dissolve starch. 



