Collected papers / edited by W. D. Halliburton.

  • King's College, London. Physiological Laboratory.
Date:
1900
Catalogue details

Licence: In copyright

Credit: Collected papers / edited by W. D. Halliburton. Source: Wellcome Collection.

Provider: This material has been provided by King’s College London. The original may be consulted at King’s College London.

    21/264 (page 405)
    II. The Crystalline Carbohydrates. The ordinary crystalline carbohydrates, dextrose, lsevulose, cane sugar, maltose, and lactose were all investigated, but as was expected with uniformly negative results as far as precipitation was concerned1. III. Starch and its Cleavage-products. Brown and Morris2, in one of their investigations on this subject point out the great variations in the accounts of the dextrins given by different observers, and state, “ This is mainly owing to the great difficulty in obtaining the dextrins in anything like a pure state, to the alteration and separation which they undergo during purification, and lastly to the very few known processes to which when isolated they can be submitted in order to determine their properties, and their points of resemblance or difference.” I have therefore made a large number of experiments on the action of neutral salts on starch and the earlier products of its hydrolysis. This section of my paper may be divided as follows: (а) Starch paste. (б) Soluble starch. (c) The erythrodextrins. (d) The achroodextrins. (e) Comparison with the products obtained by other observers. (a) Starch paste. Potato starch was used almost exclusively in my experiments. This may be purified as described by Brown and H eron. It is washed with distilled water, then with '5 °/o potassium hydrate, then with 1 °/0 hydrochloric acid, then with distilled water till the washings are neutral in reaction, and then dried at 35-40° C. A 1 Several of them, however, form compounds with neutral salts, most of which are capable of being crystallised; such are: Dextrose in combination with sodium chloride and sodium bromide. 2C6Hj20„ . NaCl. H20 C6H1206.NaCl CGH1206.2 NaCl. Galactose yields a crystalline compound with sodium chloride. With cane sugar several such compounds can be formed with sodium chloride, sodium bromide, and sodium iodide, e.g. C]2H22On. NaCl. H20. With maltose no such compounds have been prepared. See Watt’s Dictionary of Chemistry (Muir and Morley), iv. p. 530 et seq. London, 1894. 2 Brown and Morris. Journ. Chem. Hoc. xi.vii. p. 528. 1885. PU. XXII. 28