the most economical source of
energy. The term carbohydrate covers all of the simple sugars and those
substances which can be converted into simple sugars by hydrolysis; the
ones of special interest in this study are divided into three groups,
known as, Monosaccharides (C_{6}H_{12}O_{6}); Disaccharides
(C_{12}H_{22}O_{11}) and Polysaccharides (C_{6}H_{10}O_{15}).

~Monosaccharides.~--Glucose, Fructose and Galactose are substances
whose monosaccharide molecules contain one sugar radical; hence they
cannot be hydrolized to simpler sugars (sugars of lower molecular
weight). Those constituting this group of sugars are all soluble,
crystallizable and diffusible substances, which do not undergo changes
from the action of the digestive enzymes, consequently these sugars
will enter the blood stream in their original form, unless attacked by
the bacteria which inhabit the stomach and intestinal tract. The
monosaccharides are all susceptible to alcoholic fermentation. Each
member of the group is utilized in the body for the production of
glycogen and for the maintenance of the normal glucose of the blood.

~Disaccharides.~--Sucrose, Maltose and Lactose are substances
yielding, upon hydrolysis, two molecules of simple sugar: each of
these sugars is crystallizable and diffusible: all are soluble in
water, and to a less degree in alcohol--sucrose and maltose are more
soluble than lactose. When attacked by the digestive enzymes, these
sugars are changed to monosaccharides.

~Polysaccharides.~--Starch, Dextrin, Glycogen and Cellulose are
substances more complex in character than the above-mentioned groups.
They are built up of many sugar molecules, which yield upon complete
hydrolysis many molecules of simple sugar. The polysaccharides are
insoluble in alcohol, and only soluble to a certain extent in pure
water. Some members of this group swell and become gelatinous in the
presence of moisture and heat; some become of a colloidal form in
water, and will pass through filter paper; others remain unchanged.

A brief description of the various members of these different groups
of carbohydrates will assist the nurse in the ways and means of
utilizing them in the dietary to the best advantage.

~Glucose~, which is abundant in the juice of plants and fruits, and to
a more or less degree in the blood of all animals (usually about 0.1%)
occurs free in nature. This sugar is likewise obtained from many
carbohydrates, either through the act