~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.