This may be prepared either by distilling water from bitter almonds, or, as directed in the U. S. Pharmacopoeia, by dissolving the volatile oil of bitter almonds in water, through the intervention of carbonate of magnesia; one minim of the oil being used to two fluidounces of water. The latter method is preferable, as yielding a more uniform product. As the preparation is liable to change upon being kept, it should be made in small quantities at a time, as wanted for use. it may be used as a vehicle for other substances, when hydrocyanic acid is at the same time indicated, as in nervous coughs, palpitation of the heart, and various spasmodic complaints. The proportions of the mixture should be so arranged, that a tablespoonful may be given for a dose to an adult. The preparation made by distilling the almonds is of uncertain strength, and should be discarded. it is said to have been prescribed with fatal effects.