Plutarch Quaestiones Convivales 3.2.2

[2] Upon this Trypho sat silent, studying for an answer. Erato addressing himself to us youths, said: Trypho wants your assistance; help him in this dispute about the garlands, or be content to sit without any. Ammonius too bade us not be afraid, for he would not reply to any of our discourses; and Trypho likewise urging me to propose something, I said: To demonstrate that the ivy is cold is not so proper a task for me as Trypho, for he often useth coolers and binders; but that proposition, that wine in which ivy berries have been is more inebriating, is not true; for that disturbance which it raiseth in those that drink it is not so properly called drunkenness as alienation of mind or madness, such as hyoscyamus and a thousand other things that set men beside themselves usually produce. The crookedness of the bough is no argument at all, for such violent and unnatural effects cannot be supposed to proceed from any natural quality or power. Now sticks are bent by the fire, because that draws the moisture, and so the crookedness is a violent distortion; but the natural heat nourishes and preserves the body. Consider therefore, whether it is not the weakness and coldness of the body that makes it wind, bend, and creep upon the ground; for those qualities check its rise, and depress it in its ascent, and render it like a weak traveller, that often sits down and then goes on again. Therefore the ivy requires something to twine about, and needs a prop; for it is not able to sustain and direct its own branches, because it wants heat, which naturally tends upward. The snow is melted by the wetness of the leaf, for water destroys it easily, passing through the thin contexture, it being nothing but a congeries of small bubbles; and therefore in very cold but moist places the snow melts as soon as in hot. That it is continually green doth not proceed from its heat, for to shed its leaves doth not argue the coldness of a tree. Thus the myrtle and maiden-hair, though not hot, but confessedly cold, are green all the year. Some imagine this comes from the equal and duly proportioned mixture of the qualities in the leaf, to which Empedocles hath added a certain aptness of pores, through which the nourishing juice is orderly transmitted, so that there is still supply sufficient. But now it is otherwise in trees whose leaves fall, by reason of the wideness of their higher and narrowness of their lower pores; for the latter do not send juice enough, nor do the former keep it, but pour it out as soon as a small stock is received. This may be illustrated from the usual watering of our gardens; for when the distribution is unequal, the plants that are always watered have nourishment enough, seldom wither, and look always green. But you further argue, that being planted in Babylon it would not grow. It was well done of the plant, methinks, being a particular friend and familiar of the Boeotian God, to scorn to live amongst the barbarians, or imitate Alexander in following the manners of those nations; but it was not its heat but cold that was the cause of this aversion, for that could not agree with the contrary quality. For one similar quality doth not destroy but cherish another. Thus dry ground bears thyme, though it is naturally hot. Now at Babylon they say the air is so suffocating, so intolerably hot, that many of the merchants sleep upon skins full of water, that they may lie cool.