Pharmacographia : a history of the principal drugs of vegetable origin, met with in Great Britain and British India / by Friedrich A. Flückiger and Daniel Hanbury.

  • Friedrich August Flückiger
Date:
1874
Catalogue details

Licence: Public Domain Mark

Credit: Pharmacographia : a history of the principal drugs of vegetable origin, met with in Great Britain and British India / by Friedrich A. Flückiger and Daniel Hanbury. Source: Wellcome Collection.

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

    231/736 (page 205)
    variable composition, arising in part from its diverse botanical origin, its purity is not always easily ascertained. The oleo-resin usually dissolves in a small proportion of absolute alcohol: should it refuse to do so, the presence of some fatty oil other than castor oil may be surmised. To detect an admixture of this latter, one I part of the balsam should be heated with four of spirit of wine (sp. gr. -838). On cooling, the mixture separates into two portions, the upper of which will contain any castor oil present, dissolved in alcohol and the essential oil. On evaporation of this upper layer, castor oil may be recognized by its odour ; but still more positively by heating it with caustic soda and lime, when oenanthol will be formed, the presence of which may be ascertained by its peculiar smell. By the latter test an admixture of even one per cent, of castor oil can be proved. The presence of fatty oil in any considerable quantity is likewise made evident by the greasiness of the residue, when the balsam is deprived of its essential oil by prolonged boiling with water. It has been pointed out by Tomlinson.1 that the figure presented by a drop of copaiba balsam on the surface of water is extremely charac- teristic, and readily distinguishable from that of a mixture of the balsam and castor oil. We have not ascertained to what extent this test is capable of practical application. The admixture of some volatile oil with copaiba can mostly be letected by the odour, especially when the balsam is dropped on a piece of warmed metal. Spirit of wine may also be advantageously tried for the same purpose. It dissolves but very sparingly the volatile oil of copaiba: the resins of the latter are also not abundantly soluble in it. Hence, if shaken with the balsam, it would remove at once the larger portion of any essential oil that might have been added. For the recognition of Wood Oil if mixed with copaiba, see next page, note 1. Substitutes—Under this head two drugs deserve mention, namely Gurjun Balsam or Wood Oil, described at p. 8], and Oleo-resin of Hcirdwickia pinnata Koxb.—The tree which is of a large size belongs to the order Leguminosce and is nearly related to Copaifera. According to Beddome,2 it is very common in the dense moist forests of the South Travancore Ghats, and has also been found in South Canara. The natives extract the oleo-resin in exactly the same method as that followed by the aborigines of Brazil in the case of copaiba,—that is to say, they make a deep notch reaching to the heart of the trunk, from which after a time it flows out. This oleo-resin which has the smell and taste of copaiba, but a much darker colour, was first examined by one of us in 1865, having been sent from the India Museum as a sample of Wood Oil; it was subsequently forwarded to us in more ample quantity by Dr. Bidie of Madras. It is a thick, viscid fluid, which, owing to its intense tint, looks black when seen in bulk by reflected light; yet it is perfectly transparent. Viewed in a thin layer by transmitted light, it is light yellowish-green, in a thick layer vinous-red,—hence is dichromic. It is not fluorescent, nor is it gelatinized or rendered turbid by being heated to 130° C., thus differing - 1 Journ- v- (18ti4) 387- 495. with = Flora Sylvatica for Southern India, lgures. Madras, part 24 (1872), 255.