The nature and origin of the poison of Lotus Arabicus / by Wyndham R. Dunstan and T.A. Henry.

  • Dunstan, Wyndham R. (Wyndham Rowland), 1861-1949.
Date:
1901
Catalogue details

Licence: In copyright

Credit: The nature and origin of the poison of Lotus Arabicus / by Wyndham R. Dunstan and T.A. Henry. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

    4/24 (page 516)
    to whom this plant is highly attractive, both on account of its appearance and fragrant odour. There is some evidence that certain animals indigenous to Egypt have become immune to the poisonous effects of this plant. The air-dried plant, which retains to a remarkable degree its bright green colour, has a pleasant herbaceous odour, resembling that of dry hay. The attention of both the military and civil authorities in Egypt having been frequently directed to the toxic properties of this plant, the Director of Kew Gardens was consulted, and Sir W. Thiseltox-Dyer referred to us the investigation of the matter. To the interest and energy of Mr. Ernest Floyer, of Cairo, Member of the Egyptian Institute, we are very greatly indebted, especially for the trouble he has taken to collect for us in Egypt the abundance of carefully selected material required for this research. The plants collected at different stages of growth were thoroughly dried in the air before their despatch to England. Preliminary Investigation. In the preliminary examination the important observation was made that when the dried unripe plant is crushed with water and allowed to stand for a few hours it gradually develops a strong odour of prussic (hydrocyanic) acid. When this mixture was distilled, a distillate was obtained which exhibited all the chemical reactions of this compound. The amount of hydrocyanic acid produced has been determined by distilling the finely powdered dried material with water, with which it had been in contact for some hours, the distillate being collected so long as it gave the Prussian-blue reaction for hydrocyanic acid. The entire distillate was made distinctly alkaline, and the hydrocyanic acid estimated volumetrically with silver nitrate. The determinations with different portions of a consignment of plant with flowers and a few seed pods attached gave 0'304 and 0'345 per cent, of hydrogen cyanide, calculated on the air-dried material. With younger plants, bearing flower buds as well as flowers, 0‘263 per cent, was obtained. This latter result confirmed the impression gained from qualitative examination of plants of various ages, that the poison reaches its maximum at or about the period when flowering ceases and the seeds begin to develop. When the plant is extracted with alcohol, no prussic acid is found in the extract, and similarly when the plant is covered with boiling water little or no prussic acid is evolved. The production of the acid by cold water was, however, not inhibited by the presence of salicylic acid, boric acid, phenol, or other similar antiseptics, which might be expected to interfere with microbic action. The various aqueous extracts always exerted a considerable reducing power on alkaline solutions of copper salts. The production of hydrocyanic acid from the plants in the presence of cold water, a result which does not ensue from the action