Sex. Syst. Monandria, Monogynia.
(Tuberis faecula. Ph. Lond.—Fecula of the tubers; Arrow-root. Ed., D.)
History.—This plant was brought from the island of Dominica, by Colonel James Walker, to Barbados, and there planted. From thence it was sent to Jamaica. That gentleman observed that the native Indians used the root against the poison of their arrows, by mashing and applying it to the poisoned wounds. [Sloane's Jamaica, vol. i. p. 251.]
The valuable properties of the starch made from the root are mentioned by Hughes, [The Natural History of Barbados, p. 221, 1750.] in 1751, and the mode of procuring it described by Browne, [The Civil and Natural History of Jamaica, p. 112, 1789.] in 1789.
Botany. Gen. Char.—Corolla, unequal, one of the inner segments in the form of a lip. Stamens petaloid, with half an anther on its edge. Style hooded, adhering to the edge of a sterile filament. Ovary 3-celled, smooth; ovules solitary. Fruit even, dry, 1-seeded.—Caulescent plants with fleshy rhizomata or tubers. Stems branched, often dichotomous. Inflorescence terminal, panicled, jointed, with glumaceous, deciduous bracts. (Lindley.)
Sp. Char.—Culm branched, herbaceous. Leaves ovate, lanceolate, somewhat hairy underneath. Peduncles 2-flowered (Willdenow).
Rhizome white, articulated, tuberous, placed horizontally in the earth, and giving origin to several tuberous jointed stoles (stolones tuberosi), similar to itself, but covered with scales. Those stoles are often more than a foot long, and curved, so that the points rise out of the earth and become new plants (Nees and Ebermaier). Stem two or three feet high. Leaves alternate, with long, leafy, hairy sheaths. Flowers white and small.
The Maranta indica, Tussac, [Journ. Bot. iii. 41.] E., is characterized by its leaves being smooth on both sides, and by its seeds; those of M. arundinacea being violet. But, after a careful examination, Wickström declares that Tussac's plant is identical with the M. arundinacea, Linn. [Nees v. Esenb. and Eberm. Handb. d. Med. pharm. Bot.]
Hab.—West Indies. It is cultivated both in the West and East Indies, Ceylon, Sierra Leone, &c.
Composition of the Root.—According to P. C. Benzon, [Buchner's Repertorium für die Pharmacie, Bd. xvi. S. 255, 1823.] the root of the Maranta has the following composition: volatile oil, 0.07; gummy extract, 0.50; starch, 26.00; woody fibre, 6.00; albumen, 1.58; muriate of lime, 0.25; and water, 65.600.
The per centage quantity of starch obtained from the root has been thus stated by other authorities: 7.81 (Dr. J. Clark), [Medical Facts and Observations, vol. vii. 1797.] 12.5 (De Candolle), [Physiologie Vegetale, t. i. p. 187, 1832.] 21.43 (Dr. Shier [Report on the Starch-producing Plants of the Colony of Britith Guiana, p. 11, Demerara, 1647.] from roots scarcely ripe).
Extraction of the Fecula.—The starch, or fecula, is extracted from the roots (tubers) when these are about ten or twelve months old. The process is entirely a mechanical one, and is performed either by hand or by machine.
In Jamaica, it is procured as follows: The tubers are dug up, well washed in water, and then beaten in large, deep, wooden mortars to a pulp. This is thrown into a large tub of clean water. The whole is then well stirred, and the fibrous part wrung out by the hands and thrown away. The milky liquor being passed through a hair-sieve, or coarse cloth, is suffered to settle, and the clear water is drained off. At the bottom of the vessel is a white mass, which is again mixed with clean water and drained; lastly, the mass is dried on sheets in the sun, and is pure starch. [Wright, London Medical Journal, vol. viii.]
In Bermuda [Cogswell, in Cormack's Monthly Journal of Medical Science, vol. v. p. 789, 1845.] the roots are first deprived of their paper-like scales, and then rasped by a kind of wheel-rasp (something like Fig. 224, p. 228), and the fecula well washed through sieves and carefully dried.
Upon the Hopewell estate, in the Island St. Vincent, [Recent Improvements in Arts and Manufactures, by A. Ure, M. D., 1814.] the carefully-skinned tubers are washed, then ground in a mill, and the pulp washed in tinned-copper cylindrical washing-machines. The fecula is subsequently dried in drying houses. In order to obtain the fecula free from impurity pure water must be used, and great care and attention paid in every step of the process. The skinning or peeling of the tubers must be performed with great nicety, as the cuticle contains a resinous matter, which imparts colour and a disagreeable flavour to the starch. German silver palettes are used for skinning the deposited fecula, and shovels of the same metal for packing the dried fecula. The drying is effected in pans covered by white gauze to exclude dust and insects.
Commerce.—Arrow-root is brought, in tin cases and in barrels and boxes, from the West India Islands (Jamaica, Barbados, Antigua, St. Vincent, Dominica, Bermuda, St. Kitt's, Grenada, Demerara, and Berbice), Calcutta, and Sierra Leone.
The packages of West-Indian arrow-root sent to this country are lined with paper attached with arrow-root paste. When sent to this country in the hold of the ship, their contents are easily tainted by noisome effluvia.
Arrow-root is usually distinguished by the name of the island or place producing it; as Bermuda arrow-root, St. Vincent's arrow-root, Jamaica arrow-root, African or Sierra-Leone arrow-root, &c. Bermuda arrow-root is the most esteemed variety. In 1845, about 400,000 lbs. were manufactured, of which more than three-fourths came to England. Dr. Ure says that the St. Vincent's arrow-root prepared on the Hopewell estate vies with the Bermuda sort.
In commerce, the term arrow-root is frequently used generically to indicate a starch or fecula. The following are illustrations of its use in this way:—
Portland Arrow-root is obtained from Arum maculatum (see ante, p. 158).
East India Arrow-root is the fecula procured from Curcuma angustifolia, and will be described hereafter. But the West Indian plant (Maranta arundinacea) is also cultivated in the East Indies, and the fecula obtained therefrom is exported from thence, and might with equal propriety be called East India arrow-root.
Brazilian Arrowroot is the fecula of Jatropha Manihot, and will be noticed hereafter (vide Euphorbiaceae).
Tahiti Arrowroot is the fecula of Tacca oceanica, and has already been noticed (see ante, p. 221).
Properties.—The starch or fecula (amylum vel faecula marantae), called in the shops West Indian arrow-root, or simply arrow-root, is white, odourless, and tasteless. It is in the form either of a light opake white powder, or of small pulverulent masses. When passed between the fingers, it feels firm, and, when rubbed, produces a slight crackling noise. When viewed by a good pocket lens, it is seen to consist of glistening particles. When examined by a microscope, these are seen to be convex, more or less elliptical, and moderately uniform in size. [The following measurements, in parts of an English inch, of the particles of West India arrow-root, were kindly made for me by Mr. George Jackson:—Particles. Length. Breadth. 1. 0.0020. 0.0013. 2. 0.0012. 0.0009. 3*. 0.0010. 0.0008. 4. 0.0008. 0.0005. 5. 0.0006. 0.0004. 6. 0.0005. 0.0003. The most prevalent-sized particle is distinguished thus *.] The shape is more or less irregular, but often oblong, or usually somewhat ovate-oblong, frequently obscurely triangular, or oyster-shaped, or mussel-shaped. [Schleiden (Principles of Scientific Botany) describes the granules as being compound, without evident central cavity, and always exhibiting the smooth connecting surfaces; but this description does not apply to commercial West Indian arrow-root.—Raspail has depicted the grains of the fecula of Convolvulus Batatas for arrow-root (see Payen, Ann. Scien. Nat. 2de Ser. t. x. Botanique, p. 18, 1838).] After having been digested for a short time in water, one, or rarely two, mammillary processes are, in some samples, seen projecting from the surface of some of the particles. In some specimens, these processes have appeared like short spines. The rings are very distinct, though fine. The nucleus, central cavity, or hilum is usually very distinct, generally towards one end of the particle normally circular, but frequently cracked in a linear or stellate manner. When viewed by the polarizing microscope, the particles show very distinct crosses: the junction of the arms of the cross indicates the position of the hilum.
Composition or the Starch.—Arrow-root has been analyzed by Dr. Prout [Phil. Trans. 1827.] and by Payen, [Ann. des Scien. Nat. 2de Sér. Botanique, 1838, pp. 183-184.] who obtained the following results:—
|Air dried.||Dried between 20° and 212° for 20 hours.||Dried at 212° for 6 hours or longer.||Portion most easily disaggregated, dried at 212° F.||Amidon intact purified by alcohol & water, and dried at 382° F.|
The formula which agrees with Prout's third analysis is C12H10O10.
Dr. Prout regards arrow-root as a low variety of starch analogous to the low sugar of honey; while wheat-starch he considers to be the most perfect form of starch, analogous to sugar-candy.
Substitutions, Impurities, and Adulterations.—The presence of accidental impurities (such as insects, dust, &c.) maybe readily detected by alterations in the colour, odour, and flavour of the arrow-root.
Other cheaper feculas are sometimes substituted for the genuine arrow-root; especially sago-meal, potato-starch, and tapioca-starch or Brazilian arrow-root.
The fraud is readily detected by the microscope. [Lancet, Feb. 1, 1851.] When squeezed in the hand, the sago-meal crackles like arrow-root; but when submitted to microscopic examination, the truncated extremity of many of the particles giving them either a mullar shape or dihedral summit, the irregular or tuberculated surface, and the size of the particles, readily served to distinguish it from arrow-root.
Potato-starch is sometimes sold for West Indian arrow-root. I have met with it in commerce under the name of English arrow-root. It is devoid of the dull or dead white appearance presented by West India arrow-root. The naked eye, or still better a pocket lens, readily distinguishes its large glistening particles from those of genuine arrow-root. The microscope instantly detects the difference. The particles of potato-starch are larger than those of arrow-root, and have coarser and more distinct rings. Moreover, the shape of the particles serves to distinguish them (see Potato-starch). Lampadius [Pharmaceutisches Central-Blatt für 1833. S. 638.] observed that potato-starch evolves a peculiar odour when boiled with water and sulphuric acid, and that arrow-root does not evolve this odour when treated in a similar way. Arrow-root, moreover, "is destitute of that fetid, unwholesome oil, extractible by alcohol from potato-starch." [Ure, Recent Improvements in Arts, Manufactures, and Mines, p. 10, 1844.] Mixed with one and a half, or twice its weight, of concentrated hydrochloric acid, arrow-root yields an opake paste, whereas that produced by potato-starch is transparent. Arrow-root takes a longer time than potato-starch to become viscid when mixed with equal parts of acid and water. [Scharling, Pharmaceutical Journal, vol. ii. p. 417, 1843.]
Other kind of feculas, which are said to have been substituted (on account of their cheapness) for the genuine arrow-root, such as East India arrow-root or Curcuma starch (see Curcuma angustifolia), and Brazilian arrow-root or tapioca-starch (see Jatropha Manihot), are readily distinguishable by the microscope.
Physiological Effects.—By the Indians of South America, and even by some Europeans, the roots (tubers) have been supposed to possess alexipharmic properties [Sloane's Jamaica, vol i. p. 254.] But their chief if not their only real value is that of yielding the starch called arrow-root, which is a much esteemed non-nitrogenized alimentary principle, which, like some other agents of this kind (see vol. i. p. 116), are useful in the animal economy for the production of fatty and saccharine matters, lactic acid, and heat. Arrow-root is one of the most palatable and digestible of the starches.
Uses.—The roots (tubers) have been used by the South American Indians to counteract the effects of wounds inflicted by poisoned arrows. Very recently [Hamilton, Pharmaceutical Journal, vol. vi. pp. 23 and 25, 1847.] the expressed juice of the root has been lauded as an antidote to poisons taken into the stomach, and to the bites and stings of venomous insects and reptiles.
The starch or arrow-root is employed at the table as an article of food, in the forms of puddings. It forms an agreeable, non-irritating diet for invalids or infants. In irritation of the alimentary canal, of the pulmonary organs, or of the urinary apparatus, it is especially valuable as a nutritive, emollient, and demulcent.
Administration.—To invalids and infants arrow-root (the starch) is exhibited when boiled in water or milk and flavoured. Milk disagrees with some patients, and in such is of course to be avoided. The addition of sugar improves the flavour and increases the nutritive qualities. Spices, lemon juice, or wine may be employed according to circumstances.