DIGITALIS, a genus of plants of the natural order serophulariaecte, natives chiefly of the s. of Europe and temperate parts of Asia. One only, the common FOXGLOVE (D. purpurea), is a native of Britain, and is very abundant in some parts of the country, its large purple flowers often giving a gay appearance to dry banks and steep hills. It is not unfrequently admitted into flower-gardens, particularly a white-flowered variety.
Its English name, and the botanical name D. (Lat. digitale, the finger of a glove), both refer to the form of its flowers. The central and southern parts of Europe produce several species with yellow flowers, one of which, D. grandzytora, is not an uncommon ornament of gardens. D. purpurea is much valued in medicine. It was first brought into repute by Dr. Withering. Its leaves and seeds are the parts used, generally the former. They are narcotic and poiscnous. The leaves have a di°agreeable smell when fresh, and a bitter nauseous taste, and are violently emetic and cathartic; but when dried and administered iu small and repeated doses, they are diuretic, and therefore sometimes useful in dropsy; and are still more valuable on account of their sedative power over the action of the heart and the circulation of the blood, and are used in diseases of the heart, aneurisms, hemorrhages, etc. They appear also to possess some
peculiar power over the brain and nervous system, and have been employed in Insanity, epilepsy, and other diseases. They are administered generally in the form either of tincture or infusion. They ought to be collected before the flowers expand. They owe their active properties to a peculiar crystalline principle called digitalin (q.v.). The use of D. as a medicine requires great caution on account of a property which it possesses—very remarkable in a vegetable medicine—of cumulative action on the sys tem. Many if not all of the species of D. appear to possess similar properties with D. purpurea, and to be capable of being substituted for it.