Sub-order I. Araceae, Endl.
Flowers naked, unisexual.
Sex. Syst. Monoecia, Polynadria.
Arum vulgare, Lam.; Common Cuckow-pint; Wake Robin; Lords and Ladies.—A well-known, indigenous, acrid, and poisonous plant, which, by drying or by the aid of heat, loses its acridity. From the underground tubers is manufactured, in the island of Portland, a starch called Portland arrow-root or Portland sago (faecula ari; farina ari). It is procured by cleansing the roots (tubers), pounding them in a stone mortar with water, and then straining. The starch subsides from the strained liquor, and, the supernatant water being poured off, is collected and dried. [Mrs. Gibbs, Transactions of the Society of Arts, vol. xv. p. 238, 1797.] Care is requisite in the pounding of the roots on account of their acridity.
From a peck of the roots about a pound of starch is procured.
Portland arrow-root is a white amylaceous powder. Examined by the microscope, its particles are found to be exceedingly small, [The following measurements of five particles were made by Wr. Jackson:—1. 0.0004 of an English inch; 2. 0.0003; 3. 0.00022; 4. 0.00013; 5. 0.0001; 5) 0.00115; Average: 0.0023. The average size, therefore, is the 1/4348th of the inch in diameter.] circular, mullar-shaped, or polyhedral. The angular appearance of some of them arises from compression. The hilum is circular, and apparently lies in a small depression. It cracks in a linear or stellate manner. The dietetical uses of this starch are similar to those of other starches, as of the West Indian arrow-root. It makes very agreeable puddings.
The roasted tubers are esculent.
The fresh plant is an acrid poison; causing burning and swelling of the throat, vomiting, colic, diarrhoea, and convulsions. By drying, the activity of the plant is in a great measure destroyed. Medicinally, the tubers were formerly used as diuretics in dropsies, and as expectorants in chronic catarrhs. [See Murray, App. Med. vol. v. p. 44, 1790; and Alston's Lectures on the Materia Medica, vol. i. p. 387.]
The Elements of Materia Medica and Therapeutics, Vol. II, 3th American ed., was written by Jonathan Pereira in 1853.