A text-book of physiological chemistry / By Olof Hammarsten; authorized translation from the author's enl. and rev. 4th German ed. by John A. Mandel.

  • Hammarsten, Olof, 1841-1932.
Date:
1901 [©1900]
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Licence: Public Domain Mark

Credit: A text-book of physiological chemistry / By Olof Hammarsten; authorized translation from the author's enl. and rev. 4th German ed. by John A. Mandel. Source: Wellcome Collection.

Provider: This material has been provided by the Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.

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    Our knowledge of the carbohydrates and their strnctaral relationships has been very mncli extended by the pioneering investigations of Kiliais'i ' and especially those of E. Fischer.' As the carbohydrates occur chiefly in the plant kingdom it is naturally not the place here to give a complete discussion of the numerous carbo- hydrates known up to the present time. According to the plan of this work it is only possible to give a short review of those carbohydrates which occur in the animal kingdom or are of special importance as food for man and animals. Moiiosaccliarid.es. All varieties of sugars, the monosaccharides as well as disaccharides, are characterized by the termination ose, to which a root is added signifying their origin or other relations. According to the number of carbon atoms, or more correctly oxygen atoms, contained in the molecule the monosaccha- rides are divided into trioses, tetroses, pentoses, hexoses, hepioses, and so on. All monosaccharides are either aldehydes or ketones of polyhydric alcohols. The first are termed aldoses and the other ketoses. Ordinary glucosfe is an aldose, while ordinary fruit-sugar (levulose) is a ketose. The difference may be shown by the structural formula of these two varieties of sugar: Glucose = CH,(OH).CH(OH).CH(OH).CH(OH).CH(OH).CHO; Levulose = CH,(OH).CH(OH).CH(OH).CH(OH).CO.OH,(OH). A difference is also observed on oxidation. The aldoses can be con- verted into oxyacids having the same quantity of carbon, while the ketoses yield acids having less carbon. On mild oxidation the aldoses yield mono- basic oxyacids and dibasic acids on more energetic oxidation. Thus ordinary glucose yields gluconic acid in the first case and saccharic acid in the second. Gluconic acid = CH,(OII).[CH(Ori)],.COOII; Saccharic acid = COOH.[CII(OH)],.COOH. The monobasic oxyacids are of the greatest importance in the artificial formation of the monosaccharides. These acids, as lactones, can be con- verted into their respective aldehydes (corresponding to the sugars) by the action of nascent hydrogen. On the other hand they may be transformed into stereo-isomeric acids on heating with chinolin, pyridin, etc., and the stereo-isomeric sugars may be obtaihed from these by reduction. ' Ber. (1. deutsdi. chem. Gesellscb., Bdd. 18, 19, and 20. ' See E. Fisclier's lecture : Syutlieseii in der Zuckergrnppe, Ber. d. deutsch. chem. Gesellscb., Bd. 2'd, S. 2114. . An excellent work on Carbohydrates is Tollen's Kurzes Haudbuch der Kohlebydrate, Breslau, Bd. 2, 1895, and Bd. 1, 2 Auflage, 1898, which gives a complete review of the literature.