This section is from the book "A Treatise On Therapeutics, And Pharmacology Or Materia Medica Vol2", by George B. Wood. Also available from Amazon: Part 1 and Part 2.
These are the kernels of the fruit of Amygdalus communis, variety amara, or bitter almond tree, growing wild in Persia, Syria, and the north of Africa. They are brought chiefly from Mogadore, in the empire of Morocco. All that is here said of the bitter almond is equally applicable to the kernel of. the common peach, or fruit of Amygdalus Persica.
Bitter almonds, when perfectly dry, have little or no smell, but, when rubbed with water, acquire a strong odour like that of the peach blossom. Their taste is of a peculiar not unpleasant bitterness. With water they form an emulsion which contains all their active properties. They are chiefly employed to impart flavour in confectionery and cookery; but sometimes also to obtain the medical effects of hydrocyanic acid. Their emulsion is used in the cough of catarrh and phthisis, also as a lotion in skin affections, to allay itching, tingling, etc. They act in these affections partly through their demulcent properties, but chiefly through the hydrocyanic acid generated in them with the presence of water. To prepare the emulsion, half an ounce of the almond or peach kernels is to be rubbed with half a drachm of gum arabic, two drachms of loaf sugar, and eight fluidounces of water, and the liquid then strained. The dose is a tablespoonful. Bitter almonds are also an ingredient in the officinal sy-rupus amygdalae, or syrup of orgeat, which, therefore, forms a good addition to cough mixtures. Beside this, there are two officinal preparations of bitter almonds, and one non-officinal, which require a brief notice.