Substitutes—Of the other species of Nicotiana cultivated as Tobacco, N. rustica L. is probably the most extensively grown. It is easily distinguished by its greenish yellow flowers, and its stalked ovate leaves. In spite of their coarser texture, the leaves dry more easily than those of N. Tabacum, and with some care may even be made to retain their green colour. N. rustica furnishes East Indian Tobacco, also the kinds known as Latakia and Turkish Tobacco.
N. persica Lindl. yields the tobacco of Shiraz. N. quadrivalvis Pursh, N. multivalvis Lindl. and N. repanda Willd. are also cultivated plants, the last named, a plant of Havana, being used in the manufacture of a much valued kind of cigar.
SCROPHULARIACEÆ.
FOLIA DIGITALIS.
Foxglove Leaves; F. Feuilles de Digitale; G. Fingerhutblätter.
Botanical Origin—Digitalis purpurea L., an elegant and stately plant, common throughout the greater part of Europe, but preferring siliceous soils and generally absent from limestone districts. It is found on the edges of woods and thickets, on bushy ground and commons, becoming a mountain plant in the warm parts of Europe. It occurs in the island of Madeira, in Portugal, Central and Southern Spain, Northern Italy, France, Germany, the British Isles and Southern Sweden, and in Norway as far as 63° N. lat.; it is however very unequally distributed, and is altogether wanting in the Swiss Alps and the Jura.[1718] As a garden plant it is well known.
History—The Welsh “Physicians of Myddvai” appear to have frequently made use of foxglove for the preparation of external medicines.[1719] Fuchs[1720] and Tragus[1721] figured the plant; the former gave it the name of Digitalis, remarking that up to the time at which he wrote, there was none for the plant in either Greek or Latin. At that period it was regarded as a violent medicine. Parkinson recommended it in 1640 in the “Theatrum botanicum,” and it had a place in the London Pharmacopœia of 1650 and in several subsequent editions. The investigation of its therapeutic powers (1776-9) and its introduction into modern practice are chiefly due to Withering, a well-known English botanist and physician.[1722]
The word foxglove is said to be derived from the Anglo-Saxon Foxes-glew, i.e. fox-music, in allusion to an ancient musical instrument consisting of bells hung on an arched support.[1723] In the Scandinavian idioms the plant bears likewise the name of foxes bell.
Description—Foxglove is a biennial or perennial, the leaves of which ought to be taken from the plant while in full flower. The lower leaves are ovate with the lamina running down into a long stalk; those of the stem become gradually narrower, passing into ovate-lanceolate with a short broadly-winged stalk, or are sessile. All have the margin crenate, crenate-dentate, or sub-serrate, are more or less softly pubescent or nearly glabrous on the upper side, much paler and densely pubescent on the under, which is marked with a prominent network of veins. The principal veins diverge at a very acute angle from the midrib, which is thick and fleshy. The lower leaves are often a foot or more long, by 5 to 6 inches broad; those of the stem are smaller.
When magnified, the tip of each crenature or serrature of the leaf is seen to be provided with a small, shining, wart-like gland. The hairs of the lower surface are simple, and composed of jointed cells which flatten in drying; those of the upper surface are shorter.