5. Plocaria candida, Nees.—Ceylon Moss.

Sex. Syst. Cryptogamia, Algae.
(Planta, Offic.)

Synonymes.—Gracilaria lichenoides, Greville; Sphaerococcus lichenoides, Agardh; Gigartina lichenoides, Lamouroux; Fucus lichenoides, Turner; Fucus amulaceus, O'Shaughnessy; Jaffna Moss; Edible Moss.—According to Rumphius, it is called by the Malays Sajor carang and Agar agar carang; at Amboyna, it is termed Aysana and Aytsana (h. e. arbuscula ramosa), and Rumeyar waccar; at Java, Bulung; at Macassar, Dongi dongi; and at other places, Lottu lottu and Collocane.

History.—It seems to have been long known and used in the East. It has been described by Rumphius [Herb. Amboin, Pars vi. lib. xi. cap. lvi. p. 181; Alga coralloides, tab. lxxvi. 1750.], Gmelin [Hist. Fucorum, p. 113,1768.], Turner [Fuci, vol. ii, p. 124.], Nees [Hort. physic. Berol. 42, t. vi.], and Agardh [Syst. Algarum, p. 233.]. About the year 1837 it was introduced into England by Mr. Previtè; and in the year 1840 public attention was drawn to its useful properties by Messrs. Sigmond and Farre [The Ceylon Moss, Lond. 1840.].

Botany. Gen. Char.—Frond composed of large oblong-cylindrical cells containing granular endochrome, those of the surface forming moniliform, densely-packed filaments. Fructification of two kinds: 1. hemispherical, poinleted coccidia, containing a glomerule of oblong spores on a central placenta, within a pericarp of moniliform, densely crowded filaments; 2. oblong tetraspores imbedded in cells of the surface (Endlicher).

Sp. Char.—Frond cartilaginous, cylindrical, filiform, much and irregularly branched; branches smooth, spreading, acute, somewhat fastigiate. Coccidia sessile, scattered.

Rumphius mentions four kinds of Alga coralloides, which he distinguishes as the prima, secunda, tertia, and quarta, and he has figured three kinds. Nees figures two plants—one fertile, the other sterile. Turner notices two varieties: β edulis is a smaller variety, and has a remarkably flexuose frond, more thin and less branched than α: its colour is quite white.

Hab.—Ceylon, at Jaffnapatam; the islands of the Indian Archipelago.

Commerce.—It is exported to China by the islands of the Indian Archipelago. Mr. Crawfurd [History of the Indian Archipelago, vol. iii, p. 446, 1820.] says that it forms a portion of the cargoes of all the junks; the price on the spot where it is collected seldom exceeding from 5s. 8d. to 7s. 6 3/4d. per cwt. The Chinese use it in the form of jelly with sugar, as a sweetmeat, and apply it in the arts as an excellent paste. The gummy matter which they employ for covering lanterns, varnishing paper, &c., is made chiefly, if not entirely, from it.

Physical Properties.—Ceylon moss is in whitish or yellowish-white ramifying filaments of several inches in length. At the base the largest fibres do not exceed in thickness a crowquill; the smallest fibres are about as thick as fine sewing thread. To the naked eye the filaments appear almost cylindrical and filiform; but, when examined by a microscope, they appear shrivelled and wrinkled. The branchings are sometimes dichotomous, at other times irregular. Dr. Farre states that in a bale opened at Mr. Battley's, about 1/13th appeared to bear fructification. The tubercles (coccidia) are inconspicuous when dry, but when moist, are readily seen. They are hemispherical, about the size of a poppy-seed, and contain, according to Rumphius, a mass of minute, oblong, dark red spores. The consistence of Ceylon moss is cartilaginous. Its flavour is that of sea-weed, with a feebly saline taste.

Composition.—This algal has been examined chemically, in 1834, by Dr. O'Shaughnessy [Sigmond and Farre, The Ceylon Moss, p. 74, 1840.]; in 1842, by Guibourt [Journ. de Chimie Méd. t. viii. 2nde sér. p. 368, 1842.]; and in 1843, by Wonneberg and Kreyssig [Pharmaceutisches Central Blatt für 1843, p. 252.], by Bley [Ibidem, p. 409], and by Riegel [Ibidem.].

1. Mucilaginous Matter (Carrageenin?); Vegetable Jelly; Pectin; Soluble gelatine.—The mucilaginous or gelatinizing principle of Ceylon moss appears to me to agree very closely, if indeed it be not identical, with carrageenin. It has not hitherto been analyzed.

2. Starchy Matter.—This resides chiefly in the cortical portion of the algal. But the internal cell-walls become deeply stained purplish brown on the addition of iodine, as if they were composed of a starchy substance (starchy skeleton).

Chemical Characteristics.—By moistening Ceylon moss with a weak solution of ioduretted iodide of potassium, the plant acquires a purplish-brown or red colour; the younger and more delicate fibres becoming almost black. The change of colour is most intense in the cortical portion, but the internal cell-walls also become stained. By digestion in warm water, the plant softens and swells up. By boiling it in water, then compressing and rubbing it gently between two plates of glass, the larger spheroidal cells are readily separated from each other: they are stained purplish-brown by iodine. The aqueous decoction is mucilaginous, and when sufficiently concentrated, gelatinizes on cooling. Iodine colours it a dull or purplish brown, and gives an intense dark purplish colour to the undissolved residue of the plant. If the plant be immersed in diluted hydrochloric acid, slight effervescence occurs, owing to the escape of carbonic acid evolved by the action of the hydrochloric acid on carbonate of lime.

Physiological Effects.—These are similar to those of Chondrus crispus (see ante, p. 59). Ceylon moss, therefore, may be denominated nutritive (chiefly as an element of respiration, see vol. i. p. 116), emollient, and demulcent. By the continued use of it at the table, the saline constituents of the plant would not be without some influence on the system.

Uses.—In the form of decoction or jelly, it is employed as a light and readily digestible article of food for invalids and children. The residue of the decoction is not devoid of nutritive matter, and might be served and eaten like cabbage or leguminous substances; especially when the alterative influence of the saline constituents is desired. The decoction or jelly of Ceylon moss may be employed in irritation of the mucous surfaces, and in phthisis. It is not apt to occasion thirst, sickness, flatulence, heartburn, acidity, or diarrhoea.

Administration.—It may be administered in the form of decoction or jelly. Dr. O'Shaughnessy recommends that it should be steeped for a few hours in cold rain water, as the first step to its preparation; this removes a large portion of the sulphate of soda. It should then be dried by the sun's rays, and ground to a fine powder; for cutting or pounding, however diligently performed, still leaves the amylaceous matter so mechanically protected that the boiling may be prolonged for hours without extracting the starch. This grinding process, however, is seldom employed, the prepared plant being merely cut into very small pieces.

1. DECOCTUM PLOCARIAE CANDIDAE; Decoction of Ceylon Moss.—This is prepared by boiling the prepared moss in water, milk, or whey. One drachm of the plant will give a mucilaginous quality to eight ounces of water. Milk, sugar, orange or lemon juice and peel, wine, cinnamon, or other aromatics, may be used to communicate flavour. This decoction may be taken ad libitum.

2. GELATINA PLOCARIAE CANDIDAE; Jelly of Ceylon Moss.—Mr. Previtè's directions for its preparation are the following: Boil half an ounce of the prepared moss in a quart of boiling water for twenty-five minutes, or until a spoonful of the liquid forms into a firm jelly within two or three minutes after it is removed from the boiler. Flavour with wine, a little cinnamon, lemon or orange juice and peel, and sweeten according to taste. Boil the whole for five minutes, and pass it two or three times through a jelly-bag or doubled muslin. Leave it undisturbed, and it will become a firm jelly in ten minutes. If it be required perfectly clear for table use, add the white of two eggs beaten up into a whip before the second boiling, and allow it to stand for a few minutes away from the fire, with some hot coals on the top of the boiler. When clear, pass it through the jelly-bag, and leave it to congeal. Should the jelly be required particularly firm, add an ounce of moss to the quart of water.

The Elements of Materia Medica and Therapeutics, Vol. II, 3th American ed., was written by Jonathan Pereira in 1854.