Now sweet wines do not make the head heavy, as Hippocrates says in his book on Diet, which some entitle, "The Book on Sharp Pains;" others, "The Book on Barleywater;" and others, "The Book against the Cnidian Theories." His words are: "Sweet wine is less calculated to make the head heavy, and it takes less hold of the mind, and passes through the bowels easier than other wine." But Posidonius says, that it is not a good thing to pledge one's friends as the Carmani do; for they, when at their banquets they wish to testify their friendship for each other, cut the veins on their faces, and mingle the blood which flows down with the liquor, and then drink it; thinking it the very extremest proof of friendship to taste one another's blood. And after pledging one another in this manner, they anoint their heads with ointment, especially with that distilled from roses, and if they cannot get that, with that distilled from apples, in order to ward off the effects of the drink, and in order also to avoid being injured by the evaporation of the wine; and if they cannot get ointment of apples, they then use that extracted from the iris or from spikenard, so that Alexis very neatly says-- His nose he anoints, and thinks it plain 'Tis good for health with scents to feed the brain. 25. But one ought to avoid thick perfumes, and to drink water which is thin and transparent, and which in respect of weight is light, and which has no earthy particles in it. And that water is best which is of a moderate heat or coldness, and which, when poured into a brazen or silver vessel, does not produce a blackish sediment. Hippocrates says, "Water which is easily warmed or easily chilled is always lighter." But that water is bad which takes a long time to boil vegetables; and so too is water full of nitre, or brackish. And in his book upon Waters, Hippocrates calls good water drinkable; but stagnant water he calls bad, such as that from ponds or marshes. And most spring-water is rather hard. But Erasistratus says that some people test water by weight, and that is a most stupid proceeding. "For just look," says he, "if men compare the water from the fountain Amphiaraus with that from the Eretrian spring, though one of them is good and the other bad, there is absolutely no difference in their respective weights." And Hippocrates, in his book on Places, says that those waters are the best which flow from high ground, and from dry hills, "for they are white, and sweet, and are able to bear very little wine, and are warm in winter and cold in summer." And he praises those most, the springs of which break towards the east, and especially towards the north-east, for they must inevitably be clear, and fragrant, and light. Diocles says that water is good for the digestion, and not apt to cause flatulency, that it is moderately cooling, and good for the eyes, and that it has no tendency to make the head feel heavy, and that it adds vigour to the mind and body.