This section is from the book "An Experimental History Of The Materia Medica", by William Lewis.
These are, for most purposes, blanched, or freed from the outer thin acrid skin, by steeping them in hot water till it is softened sufficiently to be peeled off.
Sweet almonds, used in food, are difficult of digestion, and afford very little nourishment, un-less extremely well comminuted. As medicines, they contribute, on account of their soft unctuous quality, to blunt acrimonious humours in the first passages, and thus, sometimes, give present relief in heart-burns and other like complaints.
On expression, they yield a large quantity, near half their own weight, of oil: which, though it has no particular taste or flavour, is somewhat more agreeable to the palate than oil olive, or most of the other common expressed oik; and hence is employed medicinally, for internal uses in preference to those oils; for ob-tunding acrid juices, and softening and relaxing the solids; in tickling coughs, hoarseness, cof-tiveness, nephritic pains, etc.
On boiling almonds in water, a part of their oil separates and is gradually collected on the surface: in digestion with rectified spirit, no separation was observed. Very little of the almond is dissolved either by spirit or by water; the decoctions, made in both menstrua, leaving, on evaporation, only a small portion of a some-what unctuous sweetish matter.
On triturating the almond with water, the oil unites with the aqueous fluid, by the mediation of the mucilaginous and farinaceous matter of the kernel, into an emulsion or milky liquor: a small quantity of powdery matter remaining undissolved: almonds that have undergone the strongest action of the press, retain still so much of their oil, as to communicate a milky hue to water.
These liquors participate of the emollient virtues of the oil, and hence are prescribed in the same intentions as the oil itself; particularly in heat of urine and stranguries, whether arising from a spontaneous acrimony of the humours, or the operation of cantharides or other irritating medicines. They are given also as diluents in acute diseases; and in some cases, for supplying, in some degree, the place of animal milk, with which they have a great analogy.
An ounce, or an ounce and a half of almonds forms an emulsion of a due consistence with a quart of water; which is to be gradually poured on, after the almonds have been first thoroughly pounded. A little sugar or other grateful materials are commonly added, the palatableness of the liquor being a point of some importance, as it is in all cases intended to be drank plentifully. For molt of the intentions, in which emulsions are generally given, gum arabic is an useful addition: if the water is heated, to hasten the solution of the gum, it must stand till grown cold before it is poured on the almonds, other-wife the emulsion will be imperfect.
Emulsio communis Ph. Ed.
Lac Amygdalae Ph. Lond.
Emulsio ara-bica Ph. Ed.
The pure oil of almonds, exposed for a few days, to a heat equal to that of the human body, becomes rancid and acrimonious. Emul-sions, on the other hand, on standing for some hours, throw up a white cream to the surface, and the whey-like liquor underneath grows, not rancid, but four. Hence some ascribe to emul-sions an advantage, in inflammatory distempers, above the pure oil, of not being subject to become acrid and irritating by the heat of the body, but tending rather to a state in which they may contribute to abate inflammation. Acids, mixed with emulsions, promote the separation of the oily and serous parts, producing immediately a thick curd, nearly after the same manner as they do in animal milk.
The pure oil, triturated with a thick mucilage of gum arabic, forms a more permanent emulfion; from which the oil does not separate on standing for some days, nor on the addition of acids; though it is speedily disengaged by alkalies both fixt and volatile. One part of gum, made into a mucilage with an equal quantity of water, is sufficient for four parts of the oil. The white or yolk of an egg, and a mixture of syrup with a small quantity of volatile spirit, render the oil also soluble in water, but less perfectly.
Sweet almonds are an useful intermedium for uniting with water substances which of them-selves are not miscible with it. Camphor, and the purgative and other resins, whether native or prepared by art, triturated with about six times their quantity of almonds, dissolve along with them in water into a milky liquor, and are thus excellently fitted for being taken in a liquid form.