CORALLINA, or CORAL, in zoology, a genus belonging to the order of vermes zoophyta. The trunk is radicated, jointed, and calcareous. The species are eight, distinguished by the form of their branches, and are found in the ocean adhering to stones, bones, shells, &c. The corals were formerly believed to be vegetable substances hardened by the air; but are now known to be composed of congeries of animals, which are even endowed with the faculty of moving spontaneously.

The islands in the South Sea are mostly coral rocks covered over with earth. The little creatures, which have scarce sensation enough to distinguish them from plants, build up a rocky structure from the bottom of that sea too deep to be measured by human art, till it reaches the surface. Some of these coralline islands appear to be of a much older date than others; particularly the Friendly Islands; and it is probable that as these submarine works are continually going on, new islands may by that means frequently be produced.

When coral is newly taken up out of the sea, the small protuberances on its surface are soft, and yield, on being pressed, a milky juice which effervesces with acids. The cortical part with which the coral is all over covered is not near so compact as the internal, and may easily be taken off whilst fresh; and from this part it is usually freed before it comes to the market. The greatest coral trade is in Genoa and Leghorn. The small sprigs unfit for ornamental uses are in the shops levigated into a subtle powder; which, however, has no medicinal virtues superior to the common testacea. Coral is not unfrequently imitated by artificial compositions, some of which are made to resemble it exactly; but the abuse may be discovered by fire, the counterfeit not affording the alkaline earth which is afforded by the genuine coral. The colouring ingredients in the artificial coral are cinnamon and miumin, both of which are easily discovered. The natural coral seems to receive its colour from iron; for spirit of vitriol acquires from it a ferruginous taste; and on calcining the coral, some particles are found among the ashes that are attracted by the magnet. Sixteen ounces of coral, according to Neuman, when distilled in an open fire, yield about five scruples and an half of volatile alkaline spirit, with two or three grains of an empyreumatic oil; from the caput mortuum calcined, five scruples and a half of fixed salt may be extracted. In former times, many extraordinary virtues were expected from this substance, on account of its fine red colour; and therefore a great number of methods were tried to extract this colour by means of spirit of wine. None of these, however, succeeded. A red colour was indeed sometimes obtained, but it turned out the same whether any coral was used in the operation or not. In some of these processes, however, the coral loses its colour. One method of making the tincture is by dissolving a pound of sugar in a little water, and then adding half a pound of wax. A pound of coral boiled in this mixture loses its redness, but is found to be unaltered in other respects. In order to prepare the tincture, the wax and sugar must be dissolved in spirit of wine.