Valerian was anciently called in English Setwall, a name properly applied to Zedoary; and the root was so much valued for its medicinal virtues, that as Gerarde[1402] (1567) remarks, the poorer classes in the north of England esteemed “no broths, pottage, or physicall meats” to be worth anything without it. Its odour, now considered intolerable, was not so regarded in the 16th century, when it was absolutely the custom to lay the root among clothes as a perfume[1403] in the same way as those of Valeriana celtica L. and the Himalayan valerians are still used in the East.
Some of the names applied to valerian in Northern and Central Europe are remarkable. Thus in Scandinavia we find Velandsrot, Velamsrot, Vandelrot (Swedish); Vendelród, Venderód, Vendingsród (Norwegian); and Velandsurt (Danish)—names all signifying Vandels’ root.[1404] Valerian is also called in Danish Danmarks græs. Among the German-speaking population of Switzerland, a similar word to the last, namely Tannmark, is applied to valerian. The Denemarcha mentioned by St. Hildegard,[1405] about a.d. 1160, is the same. These names seem to point to some connexion with Northern Europe which we are wholly unable to explain.
Pentz, a pharmaceutical assistant at Pyrmont, was the first, in 1829, to draw attention to the acid reaction of the distilled water of valerian. Another German assistant, Grote, at Verden, showed in 1831 that the acidity was by no means due to acetic acid, but to a peculiar kind of acid. The latter was identified in 1843 by Dumas with the acid artificially obtained from amylic alcohol and that extracted in 1817 by Chevreul from the fat of dolphins.
Description—The valerian root of the shops consists of an upright rhizome of the thickness of the little finger, emitting a few short horizontal branches, besides numerous slender rootlets.[1406] The rhizome is naturally very short, and is rendered still more so by the practice of cutting it in order to facilitate drying. The rootlets, which are generally 3 to 4 inches long, attain ⅒ of an inch in diameter, tapering and dividing into slender fibres towards their extremities. They are shrivelled, very brittle, and, as well as the rhizome, of a dull, earthy brown. When broken transversely, they display a dark epidermis, forming part of a thick white bark which surrounds a slender woody column. The interior of the rhizome is compact, firm and horny, but when old becomes hollow, a portion of the tissue remaining however in the form of transverse septa.
The drug has a peculiar, somewhat terebinthinous and camphor-like odour, and a bitterish, aromatic taste. The root when just taken from the ground has no distinctive smell, but acquires its characteristic odour as it dries.
Microscopic Structure[1407]—In the rhizome as well as in the rootlets, the cortical part is separated from the central column by a dark cambial zone; the medullary rays are not distinctly obvious. In old rootstocks, sclerenchymatous cells are met with in the cortical tissue.
The parenchyme of the drug is loaded with small starch granules, brownish grains of tannic matter and drops of essential oil. Numerous oil ducts are met with in the outer layer of the tissue.
Chemical Composition—Volatile oil is contained in the dry root to the extent of ½ to 2 per cent., yet on an average appears scarcely to exceed ⁴/₅ per cent. This variation in quantity is partly explained by the influence of locality, a dry, stony soil yielding a root richer in oil than one that is moist and fertile. In the latter the plant may be distinguished as the variety sambucifolia, which has a less vigorous root, devoid of runners.
Schoonbroodt[1408] has shown that the most important influence is the recent condition of the root. He states that if the root is submitted to distillation when perfectly fresh, it yields a neutral water and a large quantity of essential oil. The latter has but a very faint odour, but by exposure to the air it slowly acidifies, especially if a little alkali is added, and acquires a strong smell. Valerianic Acid which is thus formed amounts to 6 per mille of the fresh root. The dried root yields a distillate of decided valerian odour, containing valerianic acid, but in proportion not exceeding 4 per mille of the root calculated as fresh.
The oil of valerian is of a very peculiar yellowish or brownish, sometimes even almost a little greenish hue, and possessing the characteristic odour of the drug. We found it to deviate the plane of polarization from 11° to 13° to the left when examined by Wild’s Polaristrobometer in a column of 50 millimetres. By submitting it to fractional distillation we noticed[1409] that it affords a magnificent blue fraction. A superb violet or blue colour is produced if one drop of the crude oil dissolved in about 20 drops of bisulphide of carbon is mixed with 1 drop of nitric acid 1·20 sp. gr. Other colorations are produced if bromine or concentrated sulphuric acid are used;[1410] even the tincture of valerian displays similar reactions.