COMPOUNDS 207 



Notice that starch has the same chemical composition 

 as cellulose (C 6 H 10 O 5 ). The chief difference between 

 the two compounds is that cellulose is the actual sub- 

 stance of which the plant is composed, while starch is 

 food stored by the plant for some future use. Thus 

 seeds sprout, and the young plant grows for a short 

 time by using the starch stored in the seed. The starch 

 in a potato serves the same purpose. 



241. Cane Sugar. Common sugar occurs in several 

 vegetable substances. It is generally obtained from 

 sugar cane or beets. The cane or beet is usually cut 

 up and bruised under water, the sugar being dissolved 

 out ; the solution of water and sugar is drawn off and 

 boiled to a syrup. As this syrup cools some of the 

 sugar forms in crystals ; these are dried and crushed to 

 make granulated sugar. The liquid that remains is 

 boiled over, and again cooled; the crystals that now 

 form are called brown sugar. After boiling the liquid 

 two or three times more, no crystals will form and the 

 syrup is then called molasses. 



Cane sugar is a carbohydrate, its symbol being 

 C 12 H 22 O n . Its uses are too well known. 



242. Dextrose. Many fruits, such as grapes, plums, 

 peaches, etc., owe their sweetness to another carbohy- 

 drate, dextrose (C 6 II 12 O 6 ). This substance is sometimes 

 called glucose, grape sugar, etc. It can be made from 

 cane sugar and is made in large quantities from starch. 

 Dextrose is about three fifths as sweet as cane sugar. 

 In fruits it forms an easily digested food. Confectioners 

 use a great deal of the dextrose that is made from starch. 



