87. Vanilla, N. F. Vanilla.
BOTANICAL CHARACTERISTICS.—A fleshy, climbing orchid with long, smooth, dark green stem sending out at the nodes aerial rootlets which fasten it to the tree or other support. Leaves sessile, fleshy, tough, veinless. Flowers pale yellowish, in loose axillary racemes. Fruit a pod.
SOURCE AND VARIETIES.—Of the genus Vanilla there are some twentythree species recognized, a few only of which are used and cured as the commercial vanilla, a product of cultivation mainly. The fruit is chiefly cultivated in Mexico and Bourbon, and to a greater or less extent in the West Indies, Java, Mauritius, Ceylon, the Fijis, and Straits Settlements.
COLLECTION AND CURING.—The fruits are collected before they are ripe, just as they begin to turn yellow, then placed between woolen blankets in a sweating-box and left there for thirty-six hours, being afterward exposed to the noonday sun just long enough to dry off the perspiration which was thus produced. This process is repeated until the fruit has a uniform blackish chocolate color, until the curer determines the process finished and the fruit ready for packing.
ARTIFICIAL POLLENIZATION OR FECUNDATION.—In Mexico and Guinea fertilization is left to natural influences, as by insects and by the wind; but in Reunion (Bourbon) artificial fecundation is resorted to because there is a total lack of the necessary insect life. Pollenization consists in holding the flower with the thumb and finger of the left hand, and, with a splinter of wood or bamboo held in the right hand, raising up the labellum between the pollen and the stigma, then with the forefinger of the left hand pressing the former down upon the latter. Transversely are seen several rib-like processes extending inward. These are the placentae which support the numerous minute seeds. Projecting into the central cavity and borne on the inner cell-wall are unicellular papillose hairs; these secrete oil and resin, which elaborate vanillin.
DESCRIPTION OF DRUG.—Linear, somewhat triangularly compressed pods from 150 to 250 mm. (6 to 10 in.) long, 8 mm. (1/3 in.) thick, attenuated at the base, where they are curved more or less into a hook; flexible; externally finely furrowed longitudinally, dark brown, shining, unctuous, often covered with an incrustation of fine, acicular crystals of vanillin; (An adulteration of benzoic acid crystals can be detected by the latter having rhomboidal form as well as characteristic reactions.) they split lengthwise into two unequal valves, showing numerous minute, lenticular, glossy black seeds imbedded in a black, oily pulp, which also contains shining, acicular crystals. The peculiar, strong, aromatic odor resides chiefly in the pulp; taste warm, aromatic, sweetish.
CONSTITUENTS.—The aroma of vanilla, chiefly depends upon a crystalline principle, Vanillin 87a (U.S.P.) (C6H3.OH.OCH3.CHO, m-methoxyp-oxybenzaldehyde), which does not exist in the green pods, but is developed during the process of curing, and forms the frosty inflorescence upon their surface. It is found in many other plants, being first made artificially from coniferin, a glucoside found in the cambium of the pine; it is now largely made from oil of cloves by reactions upon the eugenol.
Preparation of Vanillin.—Treat alcoholic extract with ether, evaporate, and treat residue with boiling water, when needles of vanillin are deposited. Prepared artificially on large scale from coniferin, C10H22O8 + 2H20, a compound occurring in the sap of the cambium in the Coniferae. This is first fermented and finally oxidized.
ACTION AND USES.—Carminative, stimulant, aphrodisiac, anti-hysteric.
Dose: 5 to 30 gr. (0-3 to 2 Gm.). It is rarely employed medicinally, being principally used as a flavor.
87a. VANILLINUM (U.S.P. IX) is described as methylprotocatechnic aldehyde. Should contain not more than 0.05 per cent. of ash.