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 well fern, 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 as soon as a small stock is received pour it out.