Chemically, the Foxglove contains a dangerous, active, medicinal principle digitalin, which acts powerfully on the heart, and on the kidneys, but this should never be given in any preparation of the plant except under medical guidance, and then only with much caution.
The purple Foxglove (Digitalis purpurea) which every one knows and admires for its long graceful spikes of elegant bell-shaped brilliant blossoms seen in our woods and hedges, is also called the Thimble Flower, or the Finger Flower, from the resemblance of these blossoms to a thimble or to the fingers of a glove. The word digitalis refers likewise to the digits, or fingers of a gauntlet. In France the title is Gants de Notre Dame, the gloves of our Lady the Virgin. Some writers give Folks' Glove, or Fairies' Glove as the proper English orthography, but this is wrong. Our name of the plant comes really from the Anglo-Saxon, Foxesglew or Fox music, in allusion to an ancient musical instrument composed of bells which were hanging from an arched support, a tintinnabulum, which this plant with its pendent bell-shaped flowers so exactly represents.
In Ireland the Foxglove is known as the Great Herb, and Lusmore, also the Fairy Cap; and in Wales it is the Goblin's Gloves; whilst in the North of Scotland it is the Dead men's Bells. We read in the Lady of the Lake there grew by Loch Katrine:—
"Night shade and Foxglove side by side,
In Devonshire the plant is termed Poppy, because when one of the bell-shaped flowers is inflated by the breath whilst the top edges are held firmly together; the wind bag thus formed, if struck smartly against the other hand, goes off with a sounding pop. The peasantry also call it "Flop a dock." Strangely enough, the Foxglove, so handsome and striking in a landscape, is not mentioned by Shakespeare, or by either of the old English poets. The "long purples" of Shakespeare refers to the orchis mascula.
Chemically, the Foxglove contains a dangerous, active, medicinal principle digitalin, which acts powerfully on the heart, and on the kidneys, but this should never be given in any preparation of the plant except under medical guidance, and then only with much caution. Parkinson speaks highly of the bruised herb, or of its expressed juice, for scrofulous swellings when applied outwardly in the form of an ointment. An officinal tincture is made from the plants collected in the spring, when two years old; also, in some villages the infusion is employed as a homely remedy to cure a cold, the herb being known as "Throttle Wort;" but this is not a safe thing to do, for medical experience shows that the watery infusion of Foxglove acts much more powerfully than the spirituous tincture, which is eight times stronger, and from this fact it may fairly be inferred that the presence of alcohol, as in the tincture, directly opposes the specific action of the plant.
This herb bears further in some districts the names "Flop Top," "Cow Flop," and "Flabby Dock." It was stated in the Times Telescope, 1822, "the women of the poorer class in Derbyshire used to indulge in copious draughts of Foxglove tea, as a cheap means of obtaining the pleasures of intoxication. This was found to produce a great exhilaration of the spirits, with other singular effects on the system." So true is the maxim, ubi virus, ibi virtus.
No animal will touch the plant, which is biennial, and will only develop its active principle digitalin, when getting some sunshine, but remains inert when grown altogether in the shade. Therefore its source of production for medicinal purposes is very important.