This section is from the book "A Treatise On Therapeutics, And Pharmacology Or Materia Medica Vol1", by George B. Wood. Also available from Amazon: Part 1 and Part 2.
Under this title, has been introduced into the U. S. Pharmacopoeia the root of Cypripedium pubescens, one of several species, which, with the common name of ladies' slipper or moccasin plant, inhabit the woods in different parts of the United Slates. They are small perennial herbs, with beautiful and conspicuous flowers, which, from their peculiar shape, have given rise to the name by which the plants are commonly designated. The medical virtues of the different species are probably identical or nearly so, and several of them are indiscriminately employed. The root of the officinal species consists of numerous somewhat contorted radicles, four or five inches long, which unite in a common head or caudex. It has an aromatic odour, and a peculiar, sweetish, pungent, and bitter taste, and imparts its virtues to water and alcohol. These appear to consist in a moderate stimulant power, directed especially to the nervous system, which renders the root useful in various nervous diseases, as hysteria, hypochondriasis, morbid sensitiveness, neuralgia, etc. The dose of the powder is about fifteen grains three times a day. A resinoid matter obtained by precipitating the tincture with water, improperly called cypripedin, has been given in doses varying from half a grain to three grains. The medicine may be administered also in infusion; and a fluid extract would probably be an eligible preparation were the remedy much used.