The seeds contain sufficient nutriment to feed the seedling whilst it is developing it roots and first real leaves. We can, of course, go further back in starting our observations of the life progress of the monarch of the forest. We can dissect the insignificant greenish flower of the Oak when the future seed (acorn) is but a single cell, a tiny bag filled with protoplasm. From that early stage to the period when the tree is first ripe for conversion into timber we span a century and a half, equal to two good human lives, and the Oak is but at the point where a man attains his majority. The Oak is built up after the fashion by which man attains to his full stature. It is a process of multiplication of weak, minute cells, which become specialized for distinct offices in the economy of the vegetable community we call a tree. Some go to renew and enlarge the roots, others to the perfecting of that system of vessels through which the crude fluids from the roots are carried up to the topmost leaf, whence, after undergoing chemical transformation in the leaf laboratory, it is circulated to all parts of the organism to make possible the production of more cells. Each of these has a special task, and it becomes invested with cork or wood to enable it to become part of the bark or the timber; or it remains soft and develops the green colouring matter, which enables it, when exposed to sunlight, to manufacture starch from carbon and water.
This is very similar to what takes place in the human organism, where the nutriment taken in is used up in the production of new cells, which are differentiated into muscle-cells, bone-cells, epidermal-cells, and so forth, building up or renewing muscles or nerves, bones or arteries; but the mechanism of distribution is different, the heart-pump doing the work of capillary attraction and gravitation. The ancients believed in the Dryads, spirits that were imprisoned in trees, and whose life was coterminous with that of the tree; and it will be seen that they had stronger physical justification for their belief than they knew. Shakespeare relates how Sycorax, the witch-mother of Caliban, imprisoned Ariel in a tree; and Huxley finely tells us that "The plant is an animal confined in a wooden case; and Nature, like Sycorax, holds thousands of 'delicate Ariels' imprisoned in every oak. She is jealous of letting us know this; and among the higher and more conspicuous forms of plants reveals it only by such obscure manifestations as the shrinking of the Sensitive Plant, the sudden clasp of the Dionæa, or, still more slightly, by the phenomena of the cyclosis."