Chemical examination of watermelon seed / by Frederick B. Power and Arthur H. Salway.

  • Power, Frederick B. (Frederick Belding), 1853-1927.
Date:
[1910]
Catalogue details

Licence: Attribution 4.0 International (CC BY 4.0)

Credit: Chemical examination of watermelon seed / by Frederick B. Power and Arthur H. Salway. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    treatment with light petroleum was subjected to distillation witn steam, but no volatile product was obtained. The contents of the distillation flask then consisted of a dark colored aqueous liquid (A) and a quantity of a black resin (B), which were separated by filtration and the resin well washed with water. The Aqueous Liquid (A). The aqueous liquid was repeatedly extracted with ether, the ethereal, liquids being washed, dried, and the solvent removed. About 0.5 gram of a viscid, brown oil was thus obtained, which deposited nothing in the cold, and which, in alcoholic solution, gave with ferric chloride a green coloration. The oily product was digested with a large volume of light petroleum, but no crystalline substance could be isolated from it. It was thus ascertained that the seed of the watermelon, unlike those of the pumpkin, do not contain salicylic acid. Treatment with Basic Lead Acetate. The aqueous liquid, which had been extracted with ether as above described, was subsequently treated with basic lead acetate, which yielded a yellowish brown precipitate. The latter was collected on a filter, thoroughly washed, and then suspended in water and decomposed by hydrogen sulphide. On filtering the mixture and concentrating the fil- trate under diminished pressure, a reddish brown liquid was obtained, which gave a bluish black coloration with ferric chloride, thus indica- ting the presence of tannin. As the liquid deposited only a little amor- phous material on standing, it was finally mixed with purified sawdust and the dried mixture extracted successively in a Soxhlet apparatus with ether, ethyl acetate and alcohol. These solvents, however, did not effect the separation of any crystalline substance. The filtrate from the basic lead acetate precipitate was treated with hydrogen sulphide for the removal of the excess of lead, filtered, and this filtrate concentrated under diminished pressure. A reddish brown, sirupy liquid was thus obtained, which contained a large amount of sugar, since it readily yielded d-phenylglucosazone, melting at 210°. The liquid gave a precipitate with potassium-mercuric iodide, and on heating with alkalies evolved ammonia, but these reactions wrere evidently due to protein products and not to the presence of an alkaloid, since the en- tire seed, when tested for substances of this class by means of Prollius’ fluid, gave a perfectly negative result. A portion of the aqueous liquid which had been purified by treatment with basic lead acetate, as above described, was heated for some time in a reflux apparatus with such an amount of sulphuric acid that the latter represented 5 per cent, by weight of the mixture. During the operation a quantity of resinous material separated, which was quite