This section is from the book "An Experimental History Of The Materia Medica", by William Lewis.
Maidenhair: an evergreen plant; with slender, smooth, shining blackish stalks; producing no manifest flower. The seeds are a fine dust, lying in roundish specks, about the edges of the backs of the leaves, which curl over and cover them.
1. Adianthum Pharm. Paris. Adianthum verum. Capillus veneris: Adianthum folio cori-andri C. B. Adiantum capillus veneris Linn. True maidenhair: about half a foot high, with several pinnae of little roundish sinuated or nearly triangular leaves towards the tops of the stalks.
2. Adiantum Canadense Pharm. Parif, Adianthum fruticofum brazilianum C. B. Adiantum pedatum Linn. Canada maidenhair: larger, with spreading branches.
The first sort grows wild in Italy and the southern parts of France, from whence the dry-leaves are sometimes brought to us. The second, a native of America, is cultivated in some of our gardens.
The leaves of both the maidenhairs have a flight sweetish roughish taste, and a pleasant but weak smell, very perceptible when boiling water is poured on them. They readily give out to the water the whole of their smell, taste, and medicinal virtue: the infusions are not ungrateful; particularly that of the Canada sort, whose flavour is both pleasanter and stronger than that of the other. Infusions or decoctions of them, infpiffated, yield a moderately rough, bitterish, mucilaginous extract. Rectified spirit of wine takes up their taste and flavour, and gains from them a deep green colour, but dis-solves little of the mucilaginous substance, in which a considerable part of their virtue consists: the extract, obtained by infpiffating the tincture, is less in quantity, and stronger in taste, than that made with water.
Maidenhair has long been held in esteem against disorders of the breast; for promoting expectoration, softening recent coughs, and allaying the tickling in the throat occasioned by defluctions of thin rheum. For these purposes, a syrup of the true sort, flavoured with a little orange-flower water, has been usually brought from France; and a syrup of the Canada sort, made with maple sugar, is sometimes received from America. The virtue of the maidenhair is obtainable, however, to much better advantage, by drinking an infusion of the herb as tea, sweetened either with sugar, or by the addition of a little liquorice. The English maidenhair has been commonly substituted in the pectoral syrups and infusions made among us: the Canada species, which appears to be superiour to both, is said to have been long made use of in France, and has lately been introduced into practice in this country.