Carbohydrates

Carbohydrates are a class of closely-related substances, all consisting of carbon, hydrogen, and oxygen, the two latter elements being present in the proportion in which they exist in water. Under this head are included amongst others the sugars, grape sugar, cane sugar, milk sugar, etc.; starch, dextrin, cellulose, gums, etc. They are frequent constituents of plants (starch, cellulose, etc.), and animal products (glycogen). Many have recently been synthetically prepared, and their constitution shown to be analogous to aldehydes or ketones. Almost all exert an action on polarised light, and most undergo fermentation by the action of different micro-organisms, the products varying with the carbohydrate and with the organism employed.