And here, too, I must not omit to give some account of pumice.2744 This name is very generally given, it is true, to those porous pieces of stone, which we see suspended in the erections known as “musæa,”2745 with the view of artificially giving them all the appearance of caverns. But the genuine pumice-stones, that are in use for imparting smoothness to the skin of females, and not females only, but men as well, and, as Catullus2746 says, for polishing books, are found of the finest quality in the islands of Melos and Nisyros2747 and in the Æolian Isles. To be good, they should be white, as light as possible, porous and dry in the extreme, friable, and free from sand when rubbed.

Considered medicinally, pumice is of a resolvent and desiccative nature; for which purpose it is submitted to calcination, no less than three times, on a fire of pure charcoal, it being quenched as often in white wine. It is then washed, like cadmia,2748 and, after being dried, is put by for keeping, in a place as free from damp as possible. In a powdered state, pumice is used in ophthalmic preparations more particularly, and acts as a lenitive detergent upon ulcerations of the eyes. It also makes new flesh upon cicatrizations of those organs, and removes all traces of the marks. Some prefer, after the third calcination, leaving the pumice to cool, and then triturating it in wine. It is employed also as an ingredient in emollient poultices, being extremely useful for ulcerations on the head and generative organs; dentifrices, too, are prepared from it. According to Theophrastus,2749 persons when drinking for a wager are in the habit2750 of taking powdered pumice first; but they run great risk, he says, if they fail to swallow the whole draught of wine at once; it being of so refrigerative a nature that grape-juice2751 will absolutely cease to boil if pumice is put into it.