Botanical Source.—Blessed thistle is an annual, branched, woolly plant, with a fibrous, whitish root, sending out several roundish, reddish stems, 1 or 2 feet high. The leaves are amplexicaul, somewhat decurrent, nearly entire, pinnated or deeply pinnatifid, more or less hairy; the upper leaves sessile; the lower petioled. The flowers are yellow, and borne in terminal bracteate heads. Involucre ovate; scales close-pressed, coriaceous, extended into a long, hard, spiny, pinnated appendage; lateral spines conical and distant. The florets of the ray are sterile, slender, and as long as those of the disk. Fruit longitudinally and regularly striated, smooth, with a broad, lateral scar. Pappus triple, as it were; the outer being the horny, short, crenated margin of the fruit; the intermediate consisting of 10 long, stiff setae; the inner, of 10 short setae; all the setae alternating with each other (L.).
History.—This plant is common to southern Europe and the Levant, and has been introduced into this and several other countries. It flowers in June, at which time the leaves and tops should be collected, as the plant is at its highest degree of medicinal power; they should be thoroughly and speedily dried, and be kept free from moisture, light, and free access of air. Their odor is faint and rather disagreeable, and their taste is exceedingly bitter. Their properties are yielded to water or alcohol, forming a pleasantly-bitter draught when infused with the former fluid, but a sickening and repulsive decoction.
Chemical Composition.—The leaves yield, upon analysis, an amorphous, brownish-yellow, bitter principle, resin, a fixed oil, gum, sugar, albumen, some salts, etc. The bitter principle was discovered, in 1839, by Nativelle and by him named cnicin (C42H56O15, Scribe), and is supposed to be the active constituent of the plant. It crystallizes in transparent white needles, which have a bitter taste, are odorless, neutral, unaffected by the atmosphere, are fused and decomposed by heat, slightly soluble in cold, but more so in boiling water, sparingly soluble in ether, but readily in alcohol. Chemically it approaches salicin. Vomiting is produced by it in doses of 5 or 6 grains; 7 or 8-grain doses have proved beneficial in periodical fevers (see Chem. Gaz., Vol. II, p. 462).
Action, Medical Uses, and Dosage.—A cold infusion is tonic; a warm infusion diaphoretic and emmenagogue; and, if strong, emetic. Used as a tonic in loss of appetite, dyspepsia, and intermittent diseases. Valuable also in the forming stage of febrile and inflammatory affections. Colds may be broken up with it, and it acts well in menstrual suppression from cold. Dose of the powder, from 10 to 60 grains; of the infusion, 2 fluid ounces; specific cnicus benedictus, 5 to 10 drops, every 4 hours.
Related Species.—Centaurea calcitrapa, Linné; Star thistle.—Europe. Naturalized to some extent in the United States. Flowers purple, and herb has a bitter taste. Virtues like those of blessed thistle.
Ɣ Centaurea cyanus, Linné; Blue bottle; Corn flower.—Europe. Naturalized and cultivated in flower gardens in the United States. Florets blue. Besides being an ingredient of some fumigating powders, these flowers have virtues similar to the preceding plants.
King's American Dispensatory, 1898, was written by Harvey Wickes Felter, M.D., and John Uri Lloyd, Phr. M., Ph. D.