4. Chondrus crispus, Grev.—Carrageen or Irish Moss.

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

Synonymes.—Chondrus polymorphus, Lamour; Sphaerococcus crispus, Agardh; curled chondrus (chondrus, from χόνδρος, cartilage).

History.—Carrageen, Irish, or pearl moss, was introduced into medicine by Mr. Todhunter, of Dublin [Reece's Monthly Gazette of Health, Jan. 1831.].

Botany. Gen. Char.—Frond cartilaginous, nerveless, compressed or flat, flabelliform, dichotomously cleft: formed internally of three strata; the inner, of densely-packed longitudinal fibres; the medial, of small roundish cells; the outer, of vertical, coloured, moniliform filaments. Fructification: 1, prominent tubercles (nemathecia) composed of radiating filaments, whose lower articulations are at length dissolved into spores (?); 2, tetraspores collected into sori, immersed in the substance of the frond (Harvey).

Sp. Char.—Frond stipitate, thickish, cartilaginous, flat or curled, segments wedge-shaped, very variable in breadth; apices truncate, submarginate, or cloven: axils obtuse; sori elliptical or oblong, concave on one side (Harvey). Fronds from 2 or 3 to 10 or 12 inches long: their substance cartilaginous, in some varieties approaching to horny, flexible and tough; their colour deep, purple-brown, often tinged with purplish-red, paler at the summit, becoming greenish, and at length white in decay.

This, says Dr. Greville, is the Proteus of marine Algae. The varieties are innumerable, and pass into one another so insensibly that it is almost impossible to define them.

Mr. D. Turner [Fuci; or, Figures and Descriptions of the Plants referred by botanists to the genus Fucus, Lond. 1808-12, 4to.] enumerates the following varieties:—

β virens; frond submembranaceous, branches dilated upwards, flattish, extreme segments long and acuminated.
γ stellatus; frond submembranaceous, branches dilated upwards, divided at their apices into very numerous clustered short laciniae.
δ equalis; frond cartilaginous, thick, all the branches equal, linear, the extreme segments obtuse.
ε filiformis; frond cartilaginous, subcylindrical, branches nearly linear, apices long and acuminated.
ζ patens; fronds subcartilaginous, channelled on one side, dichotomous, angles of the dichotomies patent.
η lacerus; frond cartilaginous, compressed, apices very narrow, elongated, branched.
θ sarniensis; frond between coriaceous and cartilaginous, branches slightly channelled on one side, dilated upwards, apices rounded and emarginate.
ι planus; frond subcoriaceous, flat, wide, branches linear, apices obtuse.
κ geniculatus; frond cartilaginous, compressed, branches nearly linear, tubercles subglobose, black, frond bent, and often broken at the tubercles.

According to Ormancey [Journal de Pharmacie et de Chimie, 3me sér., t. xii. p. 265, 1847.], carrageen is a zoophyte which he proposes to call Antipathes polymorphus. Unlike the fuci, he says, it has no canal, nerves, or roots; but, like the zoophytes, it has voluntary motion of tentaculae, sensibility, and two distinct bodies, one secreted by the other, simulating a plant.

Hab.—On rocks and stones on the sea-coast; very common.—Perennial: spring.

Preparation.—For dietetical and medicinal uses, it is collected on tho west coasts of Ireland (especially in Clare), likewise, according to Kohl [Ireland, p. 247.], in Antrim; washed, bleached (by exposure to the sun), and dried.

In Ireland, it is sometimes employed by painters and plasterers as a substitute for size.

Along with Chondrus crispus, other allied species, especially Ch. mamillosus, are sometimes collected (see Fig. 158).

Physical Properties.—The carrageen or Irish moss of commerce (muscus carragenicus) consists of fronds, which are usually from two to three or four inches long, dry, crisp, mostly yellowish or dirty white, but intermixed with purplish red portions, inodorous, or nearly so, with a mucilaginous taste. The frond is formed internally of three strata; the inner, of densely-packed longitudinal fibres; the medial, of small roundish cells; the outer, of vertical, coloured, moniliform filaments [Phycologia Britannica, vol. i. pl. lxiii. Lond. 1846.].

In warm water, the dried commercial frond swells up, and, when boiled, almost entirely dissolves. If the swollen and partially-dissolved frond be examined by the microscope, it is seen to consist of very minute, somewhat fusiform cohering cells. A calcareous meshy crust (consisting of various species of Flustra) is frequently found on the frond.

Chondrus mamillosus is found in commercial carrageen. Some samples I found to be principally composed of this species [See, also, Henschel in Dierbach, Die neuesten Entdeck. in d. Mat. Med. Bd. ii S. 276, 1843.]. The frond of this plant is more or less channelled; but the species is best distinguished by the fructification; in Ch. crispus the subhemispherical capsules are imbedded in the disk of the frond, producing a depression on the opposite side (see Fig. 156); in Ch. mamillosus, the spherical capsules are scattered over the disk of the frond, and are supported on little short stalks (Fig. 158).

Composition.—It has been analyzed by Herberger [Buchner's Repertorium, Bd. xlix. S. 200, 1834.] and by Feuchtwanger [American Journal of Sciences and Arts, xxvi.].

Subsequently, iodine has been detected in it by Sarphati [Commentatio de Iodio, Lugd. Bat. 1835.], and both iodine and bromine by Grosse [Pharmaceutisches Central Blatt für 1839, S. 159.]. (For the composition of the ashes, see p. 51.)

Carrageenin.—The mucilaginous constituent of carrageen moss is termed by some writers vegetable jelly, or vegetable mucilage, by others pectin. It appears to me to be a peculiar modification of mucilage, and I shall, therefore, call it carrageenin. It is soluble in boiling water, and its solution forms a precipitate with diacetate of lead and silicate of potash, and, if sufficiently concentrated, gelatinizes on cooling. Carrageenin is distinguished from ordinary gum by its aqueous solution not producing a precipitate on the addition of alcohol; from starch, by its not assuming a blue colour with tincture of iodine; from animal jelly, by tincture of nut-galls causing no precipitate [Berlin. Jahrb. xxxiv. Abth. i. 1834.]; from pectin, by acetate of lead not throwing down anything, as well as by no mucic acid being formed by the action of nitric acid.

According to Schmidt [Ann. der Chemie u. Pharm. Bd. li. S. 29, 1844.], the cell-walls of carrageen do not essentially differ from the contents of the cells; for, when the plant is boiled in water, the whole swells up and forms a mucilage, which may be expressed through a linen cloth, leaving behind the Flustrae and small crustaceans with which this alga is covered. By digestion for a short time with dilute sulphuric acid in a water-bath, the whole plant is converted into sugar and gum.

The composition of carrageenin dried at 212° F., according to Schmidt, is represented by the formula C₁₂H₁₀O₁₀; so that it appears to be identical with starch and sugar. Mulder [Pharmaceutisches Central Blatt für 1838, S. x00; and The Chemistry of Animal and Vegetable Physiology, by Fromberg and Johnston, Part ii. p. 239.], however, represents it by the formula C₂₄H₁₉O₁₉.

Chemical Characteristics.—The presence of carrageenin in the decoction is demonstrated by the tests before enumerated. No iodine is recognizable by nitric acid and starch. Oxalate of ammonia detects lime (or calcium) in solution, while nitrate of silver points out the presence of chlorine. Guibourt [Journ. de Chim. Méd. viii. 663.] could recognize neither sugar nor magnesia.

Physiological Effects.—Carrageen moss is nutritive: its mucilaginous matter acts as an element of respiration (see ante, vol. i. p. 116), while its inorganic constituents (phosphate of lime, potash, salts, &c.) may also serve some useful purpose in the animal economy. It is generally regarded as being readily digestible.

Medicinally, it is emollient and demulcent (see ante, vol. i. pp. 207-8).

Uses.—It is a popular remedy for pulmonary complaints (especially those of a phthisical character), chronic diarrhoea and dysentery, scrofula, rickets, enlarged mesenteric glands, irritation of bladder and kidneys, &c. As a culinary article, it has been employed as a substitute for animal jelly, in the preparation of blanc-mange, jellies, white soup, &c. A thick mucilage of carrageen scented with some prepared spirit is sold as bandoline, fixature, or clysphitique, for stiffening the hair and keeping it in form.

Administration.—It is usually exhibited in the form of decoction or jelly. It has also been employed in combination with chocolate or cocoa.

1. DECOCTUM CHONDRI; Decoction of Carrageen or Irish Moss.—Macerate half an ounce of carrageen in cold or warm water, during ten minutes; then boil in three pints of water for a quarter of an hour. Strain through linen. When properly flavoured, it may be used as a tisan or common drink. By doubling the quantity of carrageen, a mucilage (mucilago chondri) is procured. Milk may be substituted for water when the decoction is required to be very nutritious. A preparation of this kind has been called lac analepticum. Sugar, lemon-juice, tincture of orange-peel, essence of lemon, or other aromatics, as cinnamon or nutmeg, may be employed as flavouring ingredients.

2. GELATINA CHONDRI; Carrageen Jelly.—This may be prepared by adding sugar to the strained decoction and boiling down until the liquid is sufficiently concentrated to gelatinize on cooling; or by employing a larger quantity of carrageen. If milk be substituted for water, carrageen blanc-mange is obtained. Sugar and other flavouring ingredients may be employed, as above mentioned.

3. PASTA CACAO CUM CHONDRO; Pasta Cacao cum Lichene Carragheno, Ph. Dan.; Carrageen Cocoa.—The Danish pharmacopeia gives the following directions for its preparation: Roasted and decorticated Cacao Seeds reduced to a very subtile mass in a warm iron mortar; Powdered White Sugar, of each lb ij; Powdered Carrageen ℥iij. Mix, and form into quadrangular sticks. Clarus and Radius (Dierbach, Die neuesten Entdeck. in d. Mat. Med. Bd. li. S. 276, 1843.) direct carrageen, or white chocolate, to be prepared as follows: Cocoa Paste ℥iv; Powdered Carrageen ℥vj; White Sugar ℥iv; Flour, q.s. (℥vj). Mix.—These pastes are to be used like common cocoa or chocolate.

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