We have already seen some of the provisions made for the preservation, during this inclement season, of plants of larger growth, which are exposed, leafless, and bare to all the severity of a chilling atmosphere; and we are now to mention other provisions for the varied productions of the vegetable creation, which are no less admirable. One reason, as we have already hinted, why trees of great dimensions throw off their summer clothing of leaves, is, that they may more readily resist the force of the winds, which frequently blow with fury in the winter. But there are some trees which are not endowed with this property among these, the pine tribe are the most common and conspicuous. Now, remark the contrivances by which the difficulty arising from such a deviation is met. In the first place, the leaves, if they deserve that name, instead of being broad and flat, like those of other trees, are rather in the form of bristles—which shape suffers the wind to pass freely through, and offers the smallest resistance; and, in the second place, the roots of this class of trees are spread widely along the surface of the earth, laying fast hold of the soil, as they intertwine among each other, and insert their numerous fibres; by which contrivance they are able to stand firm upon their extended base, easily resisting the force of all ordinary tempests. This fact must have struck the mind of any one, who has happened to observe the great breadth of earth and of roots attached to a fir-tree overthrown by some furious storm. There is a remark, of a more general nature, which occurs here. All trees are known to attach their roots to the soil, with more or less tenacity, in proportion to their exposure to the wind. There is nothing more familiar to the wood-forester than this striking fact, or more necessary for him to know. The trees on the outside of a grove, or wood of pine, are so firmly fixed in the soil, that scarcely any tempest can uproot them; and these shelter the rest, whose hold is not so secure. Were this outer ring to be cut down, the wind, thus suddenly let in, would be sure to injure the rest, and the safety of the whole wood might be endangered. Here we find an instance of adaptation to circumstances, which cannot be too much admired. Other kinds of evergreens, which enliven the winter months, are to be found among shrubs, and some of the lower species of trees. These are more able to resist the fury of violent winds, on account of their diminutive height, which exposes a shorter, and therefore less powerful, lever to the action of this force, while their roots are equally adapted, with those of the pine, to the peculiarities of their nature. Besides this, the leaves of these hardy plants are generally of a solid texture, and glossy surface, well suited to resist the various vicissitudes of the season. Such delightful varieties seem to have been bestowed on us, for the purpose of affording relief from the stern aspect of winter; and the grounds of the rich show how well a judicious use of these, and of various herbaceous plants, can throw over the bleakness of this gloomy season, some of the charms of summer. -re If, from shrubs and trees, we turn to the numerous and useful classes of herbs, we shall find ourselves introduced into a new field of wonders. Some of these only survive till they have shed their seed in autumn; and, having thus provided for the propagation of their species, perish as individuals, and mingle with their parent earth,—ı sembling, in this respect, many species of insects. *But others survive the winter; and of these, many die down to the root, and thus, like numerous animals, burrow, as it were, underground, where, in virtue of their combined torpidity and vital energy, they remain secure from the attacks of frost, even when it penetrates to their retreats. Here some of them are secretly preparing, by mysterious internal processes, for the coming spring; while others appear to lie entirely dormant, till more genial weather awake them from their deep sleep. Again, other classes of herbaceous plants continue to brave the rigours of winter, cheering our otherwise desolate gardens and fields with their languid smile, and expanding their blossoms, or stretching their green leaves from soil bound in the iron fetters of ice, or covered with a cold but bright mantle of snow. Of those species which survive the winter, some are biennial, and others perennial; and of the former species, it has been remarked, that, though their life may be prolonged by transplanting them, and thus retarding the period of flowering and bearing seed, yet no artificial means can prevent their decay, after they have provided for the future propagation of their species, by exercising this important function. Cowper, with his usual piety and felicity, adverts to these paternal provisions of the God of the seasons :— "He marks the bounds which Winter may not pass, And, ere one flowery season fades and dies, Before closing this paper, we may just hint at another remarkable provision of Nature with regard to plants, as applicable to the present season of the year,-that, by which the vegetable principle acquires a kind of accelerated impulse, by being pent up for a more than ordinary period. Every one is familiar with the fact, that a cold spring retards the vegetation; and that, when this has been the case to a more than ordinary extent, a few days of warm weather succeeding, will cause a sudden and wonderful burst of vegetation, which soon compensates for the delay. Nature is in haste, as it were, to regain her lost time. This principle is peculiarly remarkable in very northern climates. Where the snow lies on the ground more than ten months of the year, as in Siberia and Lapland, spring, summer, and autumn, are all comprised in the short space of four or five weeks; and, du ring that period, the whole process of springing, growing, flowering, producing fruit, and ripening, is comprised. This is exemplified in a register kept of the Siberian vegetation, of which the following is a copy :July 1. Snow gone. 9. Fields quite green. August 2. Fruit ripe. And from that time, snow and ice to 23d June, when they begin to melt. This astonishing elasticity in the principle of vegetable life, is an exceedingly striking provision of the God of Nature, which indicates adaptation to a very peculiar state of climate, that cannot be sufficiently admired. Where Nature sleeps for five-sixths of the year, the plants sleep during the same period; and yet, when they awake, they run their course, like other plants, only hastening their pace, that they may accomplish it within the allotted time! FIFTH WEEK-SATURDAY. INSTINCT. In proceeding from examining the state of plants during winter, to the consideration of that of animals, the subject of Instinct forces itself on our attention. This is one of the most mysterious and wonderful of all the qualities inherent in organized beings, and, in its operations, exhibits so distinctly a Designing Cause, separate from the being which possesses it, as to be calculated, more perhaps than almost any other phenomenon, to carry to the inquiring mind a settled conviction of a supreme and intelligent Creator. Instinct has been defined to be "the operation of the principle of organized life, by the exercise of certain natural powers, directed to the present or future good of the individual;" and it has been distinguished from reason, by considering the latter as "the operation of the principle of intellectual life, by the exercise of certain acquired powers, directed to the same end." This definition, without entering into the theory with which it is connected, seems sufficiently accurate to answer our present object. Symptoms of an instinctive principle, as thus defined, are to be found in various productions of the vegetable world. Two or three instances of this kind may be mentioned : A strawberry offset, planted in a patch of sand, will send forth almost the whole of its runners in the direction in which the proper soil lies nearest. When a tree, which requires much moisture, has been planted in a dry soil, in the vicinity of water, it has been observed, that much the greater proportion of its roots have been directed toward the water. Trees which have sprung up on a bare rock, will send out their roots in every direction, till they reach the soil below. Every one is familiar with this fact, who has frequented a wooded rocky district. A fact of a similar nature, which is noticed, I think, by Dr Darwin, and which I have myself witnessed, occurred at the Abbey of Sweetheart, in Galloway, where an ash-tree, growing on the wall which surrounds the abbey, after exhausting the small quantity of soil which had collected on its site, stopped from growing for a time, and seemed to unite all its strength in sending down a root to the ground. As soon as this root had established itself in the soil, the tree began again to flourish and increase, till it grew to a considerable size. I have somewhere seen an account of a tree, which grew in the valley of the Earn, in Perthshire, if I mis *Good's "Book of Nature," vol. ii. p. 141. |