CARBOHYDRATES, ACIDS, FATS, OILS 71 



carbon) sugars. The pentoses are also simple sugars, but, 

 as we shall see, they scarcely occur in nature, being 

 obtained chiefly by splitting up certain gums. 



92. Dextrose. — ^An important simple sugar is dextrose 

 or grape-sugar, or what is known in the market as glu- 

 cose. Except in the hands of the chemist it is seldom 

 seen as crystals, although these appear in the "candying" 

 of honey and raisins. It is a constituent of molasses and 

 the sirups. Dextrose is found in practically the same 

 plants that contain saccharose, such as sorghum, maize, 

 and the fruits. So far as known, it is always associated 

 with some other sugar. On account of its difficult crystal- 

 lization and a lower degree of sweetness, it is less valuable 

 for conunercial pxirposes than cane-sugar. That which 

 appears in the market is largely made from starch by the 

 use of an acid, and it is often utilized for adulterating the 

 more costly saccharose. Many seem to regard glucose as 

 a substance deleterious to health, but in consideration of 

 the fact that, in digestion, starch and most other sugars 

 are reduced to this compound before entering the circu- 

 lation of the animal, this view does not seem to be sus- 

 tained. There is a lack of evidence to show the ill effect 

 of glucose either upon man or animals. 



93. Levulose. — ^Another simple sugar is levulose or 

 fruit-sugar, the composition of which is identical with 

 dextrose, but which has a different chemical constitution. 

 It accompanies dextrose and is found in some fruits in 

 considerable quantities, and especially in honey. It is as 

 sweet as cane-sugar, but does not form crystals with the 

 same readiness. 



94. Galactose.— This is obtained by a cleavage of 

 milk-sugar (see later) into this sugar and dextrose. It 

 may also be obtained from certain gums. 



