34 THE ELEMENTS OF PLANT FOOD 



Carbohydrates. Carbohydrates differ from hy- 

 drocarbons in that all of them contain hydrogen and 

 oxygen in the proportion to form water: 



Glucose C 6 H 12 O 6 = 6 C + 6 (H 2 O) 



Cane sugar Ci 2 H 22 On = 1 2 C + 1 1 (H 2 O) 



The most familiar carbohydrates are the sugars, 

 cellulose, starch, and gums. 



Glucoses (CeH^Oe) are the simplest forms of sugar. 

 They are also called grape sugar and dextrose. They 

 are found in all fruits, in honey, and in the liver. Com- 

 mercial glucose is made from corn starch in large 

 quantities in the United States and from potato starch 

 in Germany. It is made by boiling the starch with 

 dilute sulphuric acid. The acid is removed by treating 

 with lime and filtering. Glucose in this form is sold 

 under various names, such as corn sirup, golden drip, 

 and silver drip. If the sirup is evaporated to dry- 

 ness, crystals are formed that resemble cane sugar, but 

 they have less sweetening power than cane sugar. 

 The solid glucose is sold under the name of grape sugar. 



Note. Many candies and some grades of brown sugar are some- 

 times made of glucose or grape sugar. The comparatively low price 

 of cane sugar and the strict enforcement of state and national pure food 

 laws have stopped the practice to a great extent. 



Sucrose (Ci 2 H 22 On) is the sugar that is meant when 

 the word sugar with no qualifying adjective is used. 

 This well-known form of sugar is found in a great 

 number of fruits, vegetables, nuts, trees, and in 

 honey. The chief sources of commercial sugar are 

 sugar cane and sugar beets. First, the juice is extracted 

 by machinery, and is neutralized with lime. Second, 

 this juice is evaporated till a thick sirup remains. 



