Uses—The mucilaginous decoction and jelly which carrageen affords are popular remedies in pulmonary and other complaints; but as nutriment such preparations are much over-estimated.[2776]
Carrageen is sometimes used for feeding cows and calves; and under the name of Alga marina, for stuffing mattresses. It is largely used for industrial purposes, like other mucilaginous matter. Its mucilage serves for thickening the colours employed in calico-printing, and as size for paper and for cotton goods. In America it is used for fining beer.
Substitutes—Gigartina mammillosa[2777] J. Agardh (Chondrus mammillosus Grev.) is collected indiscriminately with Ch. crispus. It is distinguished from the latter chiefly by having the flat portion of the thallus beset with elevated or stalked tubercles, bearing the cystocarps; but it has the same properties. G. acicularis Lamouroux, a species common on the coasts of France and Spain, and having slender cylindrical branches, is occasionally collected along with Chondrus crispus. Dalmon (1874) who has examined it, asserts it to be less soluble in boiling water than true carrageen. Small quantities of other seaweeds are often present through the negligence of the collectors.
FUCUS AMYLACEUS.
Alga Zeylanica; Ceylon Moss,[2778] Jaffna Moss.
Botanical Origin—Sphærococcus lichenoides Agardh. (Gracillaria lichenoides Grev., Plocaria candida Nees), a light purple or greenish seaweed, belonging to the class Florideæ, occurring on the coasts of Ceylon, Burma, and the Malay islands.[2779]
History—Ceylon moss has long been in use among the inhabitants of the Indian Archipelago and the Chinese. It is probably one of the plants described by Rumphius[2780] as Alga coralloides. In recent times it was brought to the notice of European physicians by O’Shaughnessy.[2781]
Description—The plant, which as found in commerce is opaque and white, having been deprived of colour by drying in the sun and air, consists of cylindrical ramifying stems or filaments, ⅒ of an inch in diameter and from 1 to 6 or more inches in length. The main stems bear numerous branches, simple or giving off slender secondary or tertiary ramifications, ending in a short point. When moistened, the plant increases a little in volume, becomes rather translucent, and frequently exhibits whitish globular or mammiform fruits (cystocarps). It is somewhat friable, and after drying at 100° C. may easily be powdered. It is devoid of taste and smell, in this respect differing from most sea weeds.
Microscopic Structure—The transverse section shows a loose tissue made up of large empty cells, enclosed by a cortical zone 30 to 70 mkm. thick. This zone consists of small cells, loaded with globular starch granules, from less than 1 up to 3 mkm. in diameter, so densely packed as to form what seems at first sight a single mass in each cell. In the larger cells the granules are attached to the walls; they do not display in polarized light the usual cross. The thick walls of the cells show a stratified structure, especially after having been moistened with chromic acid; on addition of a solution of iodine in an alkaline iodide, they assume a deep brown, but the starch granules, which also abound in the cystocarps, display the usual blue tint.
Chemical Composition—The drug, as examined by O’Shaughnessy, yielded in 100 parts of vegetable jelly 54·5, starch 15·0, ligneous fibre (cellulose?) 18·0, mucilage 4·0, inorganic salts 7·5.