20. Apples are an universal fruit. Mnesitheus the Athenian, in his treatise on Eatables, calls them Delphian apples; but Diphilus says, that "those apples which are green and which are not yet ripe, are full of bad juice, and are bad for the stomach; but are apt to rise to the surface, and also to engender bile; and they give rise to diseases, and produce sensations of shuddering. But of ripe apples, he says, that the sweet ones are those with most juice, and that they are the most easily secreted, because they have no great inflammatory qualities. But that sharp apples have a more disagreeable and mischievous juice, and are more astringent. And that those which have less sweetness are still pleasant to the palate when eaten; and, on account of their having some strengthening qualities, are better for the stomach. And moreover, that of this fruit those which are in season in the summer have a juice inferior to the others; but those which are ripe in the autumn have the better juice. And that those which are called ὀρβίκλατα, have a good deal of sweetness combined with their invigorating properties, and are very good for the stomach. But those which are called σητάνια and also those which are called πλατώνια, are full of good juice, and are easily secreted, but are not good for the stomach. But those which are called Mordianian are very excellent, being produced in Apollonia, which is called Mordius; and they are like those which are called ὀρβίκλατα. But the Cydonian apples, or quinces, some of which are called στρούθια, are, as a general rule, better for the stomach than any other kind of apple, most especially when they are full ripe." But Glaucides asserts that the best of all fruits which grow upon trees are the Cydonian apples, and those which are called phaulia, and strouthia. And Philotimus, in his third book, and also in his tenth book of his treatise on Food, says--"Of apples, those which come in season in spring are by far more indigestible than pears, whether they are both unripe, or whether they are both ripe. But they have the properties of juicy fruits; the sharp apples, and those which are not yet ripe, resembling those pears which have a harsher taste and which are in a certain degree sour; and they diffuse over the body a juice which is said to be corrosive. And, as a general rule, apples are not so digestible as pears; on which account those who are less addicted to eating them are less troubled with indigestions, and those who are most fond of them are the most liable to such inconvenience. But, as I said before, a corrosive juice is engendered by them, as is stated by Praxagoras, and as is shown by the fact that those things which are not digested will have the juice thicker. (And I have already said that, as a general rule, apples are less digestible than pears.) And the harsh and sour apples are in the habit of engendering thicker juices.