The word carbohydrate means carbon combined with water; that is, the element carbon is combined with hydrogen and oxygen, which exist in the carbohydrate compound in the same proportion as they exist in water imply that they have the same physiological effect in the animal body.

The carbohydrates are closely related chemically to the aldehydes and the alcohols, so far as their composition is concerned (See "Aldehydes and Ethers," Lesson III (Organic Chemistry), p. 93), but this does not.

Classification Of Carbohydrates

The carbohydrates are divided by the chemist into three classes known as,

A. Monosaccharids

B. Dlsaccharids

C. Polysaccharids

The principal subdivisions found in these classes of carbohydrate foods are given in the following table, arranged in the order of their importance:

Monosaccharids

Disaccharids

Polysaccharids

1 Glucose or grape-sugar (formerly called dextrose)

1 Cane-sugar

1 Starch

2 Pentoses

(of which there are several)

2 Maltose

2 Glycogen

3 Lactose

3 Cellulose

3 Levulose

4 Gums

4 Galactose

5 Inulin