arwin was a medical doctor and the Loves of the Plants inevitably has many references to the medicinal and poisonous properties of many plants, in this case the common foxglove (Digitalis purpurea):
Assumes bright DIGITALIS' dress and air,
Her ruby cheek, white neck, and raven hair;
Four youths protect her from the circling throng,
And like the Nymph the Goddess steps along.—
—O'er Him She waves her serpent-wreathed wand,
Cheers with her voice, and raises with her hand,
Warms with rekindling bloom his visage wan,
And charms the shapeless monster into man.
[Loves of the Plants, Canto 2, ll. 425-32]
Darwin’s explanatory note: “Digitalis”
Of the class Two Powers. Four males, one female, Foxglove. The effect of this plant in that kind of Dropsy, which is termed anasarca, where the legs and thighs are much swelled, attended with great difficulty of breathing, is truly astonishing. In the ascites accompanied with anasarca of people past the meridian of life it will also sometimes succeed. The method of administering it requires some caution, as it is liable, in greater doses, to induce very violent and debilitating sickness, which continues one or two days, during which time the dropsical collection however disappears. One large spoonful, or half an ounce, of the following decoction, given twice a day, will generally succeed in a few days. But in more robust people, one large spoonful every two hours, till four spoonfuls are taken, or till sickness occurs, will evacuate the dropsical swellings with greater certainty, but is liable to operate more violently. Boil four ounces of the fresh leaves of purple Foxglove (which leaves may be had at all seasons of the year) from two pints of water to twelve ounces; add to the strained liquor, while yet warm, three ounces of rectified spirit of wine. A theory of the effects of this medicine, with many successful cases, may be seen in a pamphlet, called, "Experiments on Mucilaginous and Purulent Matter," published by Dr. Darwin in 1780. Sold by Cadell, London.
Last modified 23 April 2018