The Digitalis purpurea, which is the source of all our medicinal preparations, is a biennial or perennial with numerous drooping, purple-spotted (occasionally white) or purple flowers, an erect stem from twelve to fifty inches high, and large alternate, ovate, lanceolate, crenate, rugose leaves of downy character, espe cially on their pale- or light- reddish brown under-surfaces, and tapering into winged roof-stalks. The leaves, which constitute the official digitalis, should be of the second year's growth—when they are much more oval, and also more active than those of the first year—and gathered either in July or late in June, before the small, round, gray-brown seeds begin to ripen, and when about two-thirds of the flowers have expanded; they should also be dried in the dark, in baskets, over a mod erately-heated stove or in a brick oven, and if properly cured will exhibit a dark-green hue and an almost total lack of odor, except that which generally ac crues to dried herbs and leaves and fre quently is described as "tea-like"; they have a decided nauseous and bitter taste. Much of the uncertainty that accrues to the medicinal nse of digitalis is doubt less due to improper seasons of plucking, improper drying or packing, and age; for even the best qualities and most care fully collected and husbanded, even when pressed. and wrapped in stout paper, or kept in tins that are not her metically sealed, manifest distinct loss of remedial virtues after a few months, and may become practically inert at the expiration of a year. Digitalis-leaves,
too, as found in open market, more espe cially the cheaper varieties, are probably not of D. purpurea; or the latter may be adulterated with leaves of the com mon potato, the black nightshade or black mullein (Solanum tuberosum, S. nigrum, and Verbuscum nigrum) or all three, or Coniza squamosa, which, in a dry state, somewhat resemble those of the purple fox-glove. Such sophistica tion, however, may be detected by boil ing one of the suspected leaves in the smallest possible quantity of water, pour ing upon an opalescent plate, and adding a drop of ferric chloride: if a green re action occurs, the leaf is digitalis; if blue, it is not.
Preparations and Doses. — Digitalis leaves, powdered, 'A to 3 grains.
Digitalis abstract, 1/2 to 1 grain (Squibb's, 2 to 5 grains).
Digitalis infusion (B. P.), 1 to 4 drachms (U. S. P., 2 to drachms).
Digitalis extract, solid, '/, to 1/2 grain.
Digitalis, fluid extract and normal liquid, 1 to 2 minims.
Digitalis tincture (B. P.), 5 to 40 minims.
Digitalis tincture (U. S. P.), 3 to 30 minims.
Digitalis, ethereal tincture, 2 to 8 minims.
Digitalis-vinegar (G. P. digitalis, 1; alcohol, 1; vinegar, 9 parts), 10 to 30 minims.
Digitalisin (concentration), 1/„ to 1/, grain.
Digitalein (Schmiedeberg's), 1/„ to 1/„ grain.
Digitaleine (Nativelle's). See DIGI