Lobelia, Indian Tobacco; F. Lobelie enflée; G. Lobeliakraut.
Botanical Origin—Lobelia inflata L., an annual herb, 9 to 18 inches high, with an angular upright stem, simple or more frequently branching near the top, widely diffused throughout the eastern part of North America from Canada to the Mississippi, growing in neglected fields, along roadsides, and on the edges of woods, and thriving well in European gardens.
History—Lobelia inflata was described and figured by Linnæus[1460] from specimens cultivated by him at Upsala about 1741, but he does not attribute to the plant any medicinal virtues.
The aborigines of North America made use of the herb, which from this circumstance and its acrid taste, came to be called Indian Tobacco. In Europe it was noticed by Schöpf,[1461] but with little appreciation of its powers. In America it has long been in the hands of quack doctors, but its value in asthma was set forth by Cutler in 1813. It was not employed in England until about 1829, when, with several other remedies, it was introduced to the medical profession by Reece.[1462]
Description—The leaves are 1 to 3 inches long, scattered, sessile, ovate-lanceolate, rather acute, obscurely toothed, somewhat pubescent. The edge of the leaf bears small whitish glands, and between them isolated hairs which are more frequent on the under than on the upper surface. They are usually in greater abundance on the lower and middle portions of the stem.
The stem of the growing plant exudes when wounded a small quantity of acrid milky juice, contained in laticiferous vessels running also into the leaves. The inconspicuous blossoms are arranged in a many-flowered, terminal, leafy raceme. The five-cleft, bilabiate corolla is bluish with a yellow spot on the under lip, its tube being as long as the somewhat divergent limb of the calyx.
The capsule is ovoid, inflated, ten-ribbed, crowned by five elongated sepals which are half as long as the ripe fruit. The latter is two-celled, and contains a large number of ovate-oblong seeds about ¹/₅₀ of an inch in length, having a reticulated, pitted surface.
The herb found in commerce is in the form of rectangular cakes, 1 to 1¾ inches thick, consisting of the yellowish-green chopped herb, compressed as it would seem while still moist, and afterwards neatly trimmed. The cakes arrive wrapped in paper, sealed up and bearing the label of some American druggist or herb-grower.
Lobelia has a herby smell and, after being chewed, a burning acrid taste resembling that of tobacco.
Chemical Composition—Lobelia has been examined by Procter, Pereira (1842), Reinsch (1843), Bastick (1851), also by F. F. Mayer.[1463] The first-named chemist[1464] traced the activity of the plant to an alkaloid which he termed Lobelina, and his observations were confirmed by the independent experiments of Bastick.[1465] Lewis (1878) obtained it by mixing the drug with charcoal and exhausting the powder with water containing a little acetic acid. The liquid is cautiously evaporated to the consistency of an extract and triturated with magnesia, from the excess of which the aqueous solution of lobeline is separated by filtration. It is agitated with amylic alcohol (or ether), which by spontaneous evaporation affords the alkaloid. The latter is again dissolved in water and filtered through animal charcoal; from the dried powder lobeline is to be removed by ether.