A manual of pharmacy / By William Thomas Brande.

  • Brande, William Thomas, 1788-1866.
Date:
1833
Catalogue details

Licence: Public Domain Mark

Credit: A manual of pharmacy / By William Thomas Brande. Source: Wellcome Collection.

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

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    over may be tested by adding to it a solution of green vitriol, precipitating the oxide of iron by slight excess of pure potassa, and then acidulating with muriatic acid, so as to redissolve the precipitate : a blue tint appears if prussic acid were present. When, however, it is not discernible by its odour, other methods are equivocal. AMYLU yi—The Starch of Wheat Triticum Hibernum ^ Winter-Wheat.—This important grain was first cultivated in Sicily. When wheat, swollen and softened by steeping in water, is subjected to pressure, the milky juice which exudes, being diffused through water, deposits a fine impalpable pow- der, which, when duly washed and carefully dried, splits into columnar masses, known as common starch. It has usually a yellowish hue, which is covered in the starch of commerce by the addition of smalt, or, as in Hall's patent process, is removed by the action of chlorine. For medical use, however, the pure and genuine starch should be used, its colour being unimport- ant. Starch is marked by well-defined chemical characters. It is insoluble in cold water, but readily dissolves in water at 160°, and at 180° it forms a thick jelly, which in warm weather soon liquefies, and becomes mouldy, sour, and very fetid. The diluted jelly of starch is copiously precipitated by subacetate of lead, and, when solution of iodine is added to it, a very charac- teristic blue compound is immediately formed. Starch, which has been heated till it acquires a pale brown colour, loses its peculiarities, and is converted into a substance soluble in cold water, not precipitable by iodine, and having the leading chemical characters of gum. Starch is a very nutritious article of food, and exists abun- dantly in the greater number of esculent grains and roots. A warm solution of starch is often employed as a vehicle for opium and other sedatives, when administered in the form of enema. For this purpose the mucilago amyli is directed in the PharmacopoRia. Several substances, agreeing in essential characters with the starch of wheat, have long been used as common articles of food, especially in the diet of invalids. One of the commonest and most pleasant of these is arrow-root, which professes to be the fecula of the root of the maranta anindlnacea, but for which potato-starch is, it is said, often substituted. Good arrow-root should be free from all musty flavour, white, insipid, and form a consistent jelly when dissolved in eight parts of boiling water. Sago is obtained from the pith of several species of palm, and is granulated by passing it, when half dry, through a coarse sieve. Tapioca and cassava are procured • Cl. 3. Ord. 2. Triandria Monogynia. Nal. Ord. Grainina.