Carbohydrate

(kar-bo-hi1 ’-drat) [carbo, coal; vSup, water]. An organic substance containing six carbon atoms or some multiple of six, and hydrogen and oxygen in the proportion in which they form water; that is, twice as many hydrogen as oxygen atoms. The carbohydrates form a large cla of organic compounds, and may be arranged into three groups: the glucoses (monoses); the disaccharids, or sugars; and the poly sac char ids. The glucoses are the aldehyd derivatives or ketone-derivatives of the hex a hydric alcohols, into which they may be converted by the absorption of two hydrogen atoms. They are mostly crystalline substances, very soluble in water, but di olving with difficulty in alcohol. They po e a sweet taste. The disaccharids and poly sac char ids are ethereal an hydrids of the glucoses. All of them may be converted into the glucoses by hydrolytic decomposition. The disaccharids are ether like an hydrids of the hexoses. 173