Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: CHAPTER III. THE CARBOHYDRATES AND RELATED BODIES. Under the term carbohydrate it has long been customary to include a number of bodies with closely related properties and similar composition, which may be expressed by such simple formulas as C6H10O6, C0H12O6, or multiples of these. The term carbohydrate came into use long before the structure of the bodies in question was known. It is now possible to describe these substances in their relations to the fundamental hydrocarbons or alcohols and this classification will be therefore briefly explained. NATURE OF THE CARBOHYDRATES. In their chemical behavior these bodies resemble aldehydes or ke- tones in certain important characteristics. Like the latter they are often strong reducing substances and most of them form combinations with phenyl hydrazine. These and other properties suggest that they may be considered as aldehyde or ketone derivatives of the poly- hydric alcohols, which relationship is shown by the table on pages 18 and 19, which contains also some acid derivatives for further illustration. Some of the bodies in the table are naturally occurring substances and are highly important, but most of them are artificial. The aldo- hexoses and the ketohexoses are closely related to two groups of more complex bodies, in which cane sugar and starch are the best illustrations, and with them form the important class of carbohydrates in the more restricted sense. CARBOHYDRATES PROPER. Following the usual classification we have then: Monoses, or monosaccharides, Saccharodioses, or disaccharides, Saccharotrioses, or trisaccharides, Polysaccha rides. These bodies are mostly of vegetable origin, but some, such as sugar of milk, are found in the animal kingdom. The synthetic preparation of some of these sugars h...