This section is from the book "A Text Book Of Materia Medica, Being An Account Of The More Important Crude Drugs Of Vegetable And Animal Origin", by Henry G. Greenish. Also available from Amazon: A Text Book of Materia Medica : Being an Account of the More Important Crude Drugs of Vegetable and Animal Origin.
Two varieties of serpentary, or, as it is sometimes termed, snakeroot, are official in the British Pharmacopoeia, viz. Virginian snakeroot and Texan or Red River snakeroot.
Virginian snakeroot is obtained from Aristolochia Serpentaria, Linne (N.O. Aristolochiaceoe), a small herbaceous plant with slender perennial rhizome, growing in the United States, to the east of the Mississippi.
Texan or Red River snakeroot is the produce of Aristolochia reticulata, Nuttall, a rather stouter plant, growing, as its name indicates in the south-western States.
The drug is collected in the autumn and dried. It was known in England in 1632, its use having been undoubtedly learnt from the American Indians, and it found a place in the London Pharmacopoeia of 1650.
The snakeroot at present in commerce is the variety known as Texan, and is derived from A. reticulata. It consists of a short, slender, rhizome about 25 mm. long and 3 mm. thick, to the flanks and lower surface of which are attached numerous long, curved, but not wiry or interlacing roots; these are comparatively stout, being frequently half the thickness of, or even as thick as, the rhizome itself, and seldom much shrivelled. The latter is usually horizontal, but not unfrequently assumes an oblique or even vertical position, and gives off from its upper surface (or from one side) numerous closely approximated slender aerial stems. These, when they die down, leave short portions, bearing the scars of leaves, attached to the rhizome; occasionally a fruiting stem may also be formed
Fig. 196. - Serpentary rhizome. A, Virginian; B, Texan. Natural size.
Both rhizome and roots are brittle, breaking with a short fracture. The former exhibits in transverse section a whitish pith that is distinctly eccentric, being much nearer to the upper than the under surface of the drug; the wood-bundles are numerous, yellow and curved, the bark yellowish brown and thin; the section of the root shows a slender yellow wood and a thick white bark.
The drug, by far the greater part of which consists of the roots, has a tolerably uniform yellowish brown colour, a characteristic camphora-ceous odour, and a strong, disagreeably bitter and acrid taste.
Virginian snakeroot, which appears to be seldom imported, differs from the foregoing in having a shorter and thinner rhizome and thinner wiry, interlacing roots forming little matted masses, but resembles it in colour, odour, and taste.
The student should observe
(a) The slender rhizome with portions of the stem arising from the upper surface in close succession, (6) The eccentric position of the pith, (c) The very characteristic odour and taste; and should compare the two varieties with one another, noting the differences alluded to. He should further compare the Texan variety with
(i) Small specimens of valerian root, which possess a short erect rhizome from which a single stem arises and which has a very different odour and taste. (ii) The rhizome of Indian pink, which is darker and has neither the eccentric pith, the odour, nor taste that characterise serpentary.
Serpentary rhizome contains volatile oil (about 1 per cent.), tannin, and a bitter principle, apparently an alkaloid, crystallising in light yellow needles. The latter is probably identical with Chevalier and Fenuelle's amorphous aristolochine, and with the aristolochine isolated by Hesse from A. argentina, Grisebach.
Serpentary possesses local and general stimulant and tonic properties closely resembling those of valerian and cascarilla. It is occasionally used in nervous, despondent, and excitable conditions, as well as in low fevers and febrile states.
Fig. 197. - Serpentary rhizome. A, longitudinal section of rhizome and roots: tc, remains of aerial stems; rd, roots; rh, rhizome. B, transverse section of rhizome, magnified 3 diam. (Berg).