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 habit[2750] 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-juice[2751] will absolutely cease to boil if pumice is put into it. CHAP. 43. (22.)—STONES FOR MORTARS USED FOR MEDICINAL AND OTHER PURPOSES. ETESIAN STONE. THEBAIC STONE. CHALAZIAN STONE. Authors, too, have paid some attention to the stones in use for mortars, not only those employed for the trituration of drugs and pigments, but for other purposes as well. In this respect they have given the preference to Etesian[2752] stone before all others, and, next to that, to Thebaic stone, already mentioned[2753] as being called “pyrrhopœcilon,” and known as “psaranus” by some. The third rank has been assigned to chrysites,[2754] a stone nearly allied to Chalazian[2755] stone. For medicinal purposes, however, basanites[2756] has been preferred, this being a stone that remits no particles from its surface.[2757] Those stones which yield a liquid, are generally looked upon as good for the trituration of ophthalmic preparations; and hence it is, that the Æthiopian stone is so much in request for the purpose. Tænarian stone, they say, Phœnician stone, and hæmatites, are good for the preparation of those medicinal compositions in which saffron forms an ingredient; but they also speak of another Tænarian stone, of a dark colour, which, like Parian[2758] stone, is not so well adapted for medicinal purposes. We learn from them, too, that Egyptian alabastrites,[2759] or white ophites,[2760] from the virtues inherent in them, are considered still better adapted for these purposes than the kinds last mentioned. It is this kind of ophites, too, from which vessels, and casks even, are made. CHAP. 44.—STONE OF SIPHNOS. SOFT STONES.