CHAP. 27.—INDICUM.

Next in esteem to this is indicum,[1] a production of India, being a slime[2] which adheres to the scum upon the reeds there. When powdered, it is black in appearance, but when diluted in water it yields a marvellous combination of purple and cæruleum. There is another[3] kind, also, which floats upon the surface of the pans in the purple dye-houses, being the scum which rises upon the purple dye. Persons who adulterate it, stain pigeons' dung with genuine indicum, or else colour Selinusian[4] earth, or anularian[5] chalk with woad.

The proper way of testing indicum is by laying it on hot coals, that which is genuine producing a fine purple flame, and emitting a smell like that of sea-water while it smokes: hence it is that some are of opinion that it is gathered from the rocks on the sea-shore. The price of indicum is twenty denarii per pound. Used medicinally, it alleviates cold shiverings and defluxions, and acts as a desiccative upon sores.

1. Indigo, no doubt, is the colour meant. See B. xxxiii. c. 57.

2. It is the produce of the Indigofera tinctoria, and comes from Bengal more particularly. Beckmann and Dr. Bancroft have each investigated this subject at great length, and though Pliny is greatly mistaken as to the mode in which the drug was produced, they agree in the conclusion that his "indicum" was real indigo, and not, as some have supposed, a pigment prepared from isatis, or woad.

3. This passage, similar in many respects to the account given by Dioscorides, is commented on at great length by Beckmann, Hist. Inv. Vol. II. p. 263. Bohn's Edition.

4. See Chapter 56 of this Book.

5. See Chapter 30 of this Book.