The organic constituents of plants and vegetable substances and their chemical analysis / by G.C. Wittstein ; authorised translation from the German original, enlarged with numerous additions, by Baron Ferd. von Mueller.

  • Georg Christian Wittstein
Date:
1878
Catalogue details

Licence: Public Domain Mark

Credit: The organic constituents of plants and vegetable substances and their chemical analysis / by G.C. Wittstein ; authorised translation from the German original, enlarged with numerous additions, by Baron Ferd. von Mueller. Source: Wellcome Collection.

    68/358 page 46
    [According to the researches made by Kraus, Sorby and others on the green colouring matters of leaves, spectrum analysis has revealed the existence of at least ten different colouring substances more or less separable by means of sulphide of carbon, alcohol and water, used in varying combinations. Amongst these substances are a blue-green and a yellow-green, called respectively blue and yellow chlorophyll, and five yellow substances: orange xantho- phyll, xanthophyll, yellow xanthophyll, orange lichnoxanthin and lichnoxanthin. As these colouring matters are rapidly decomposed by acids, Fremy's blue and yellow Chlorophylls are but products of decomposition. Of the above colouring matters, orange xan- thophyll occurs in considerable quantity in Oscillatorise, blue chlo- rophyll in olive Algse, xanthoj)hyll in Porphyra vulgaris (Algse), yellow xanthophyll in vai'ious pale-yellow flowers as Chrysanthe- mums, &c., and lichnoxanthin in Clavaria fuciformis. Xanthophyll and yellow xanthophyll give absorption-bands, not lichnoxanthin. On addition of a little hydrochloric acid to the alcoholic solutions, the first and the third of the three last-named matters fade slowly without altering their colour, while the second is changed into another yellow substance with two absorption-bands and then into deep blue. These three yellow substances are all soluble in sul- phide of carbon, they exist in green leaves and also generally in yellow flowers though mixed in different proportions.] [Solutions of Chlorophyll are decomposed by small quantities of hydrochloric acid, and yield on filtration a solid black residue and a yellowish-brown liquid. The latter, on addition of ipore hydro- chloric acid, assumes a deep-green colour and yields by filtration a yellow residue and a pure blue liquid. The above black matter shows, according to Filhol, a crystalline structm'e of radiated needles under the microscope in the case of Monocotyledons, but is amorphous with Dicotyledons. It dissolves very sparingly in cold alcohol of 85%, abundantly on boiling, also in ether and ben- zol with yellowish-brown, in sulphide of carbon with yellow, in chloroform with violet, and in acetic acid with blue-violet colour. Concentrated hydi-ochloric and sulphuric acids dissolve it slowly with green colour, probably under decomposition. The solution of the crystalline black matter in acetic acid assumes a splendid green colour when mixed with traces of the acetates of copper or zinc and heated to boiling.] Ch0lestearill = Ci8 H24 0 + HO. Exists, according to recent investigations, also in the vegetable kingdom and especially in the seeds and young parts of various plants (in malt, itc.) From peas it is obtained in the following manner. Digest with warm alcohol of 94°/^, evaporate to honey-consistence, dissolve in water, add oxyd of lead, boil until clear, allow to cool, throw away the water, treat again with hot alcohol, remove the lead in the tinctures by
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