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itself towards the light; or, if made to grow in a flower-pot, with its head downward, it will turn its head upward, according to the natural position of a plant. If a root be uncovered, and not exposed to much heat, and a wet spunge is placed near it, but in a direction opposite to that in which the root is proceeding, in a short time the root will turn towards the spunge. In this way the direction of roots may be varied at pleasure.

All plants make the strongest efforts by inclining, turning, and even twisting their stems and branches, to escape from darkness and shade, and to procure the influences of the sun. If a vessel of water be placed within six inches of a growing cucumber, in twentyfour hours the cucumber alters the direction of its branches, and never stops till it comes into contact. with the water. When a pole is placed at a considerable distance from an unsupported vine, the branches of which are proceeding in a contrary direction from that of the pole, in a short time it alters its course, and stops not till it clings around the pole. But the same vine will carefully avoid attaching itself to low vegetables nearer to it, as the cabbage. Hence Pliny and Cicero remark, that the vine hates the colewort and cabbage ;* as if it possessed the faculty of perception and the power of choosing.

The vine hates the cabbage and all kinds of pot-herbs."

Pliny.

"The vine is said to avoid the colewort and cabbage, if planted near it, as if they were noxious and pestilential."

Cicero.

In his Philosophy of Natural History, Smellie has given several examples of different kinds of motion in the vegetable kingdom.

"When the roots of a tree meet with a stone, or other obstacle, in order to avoid it, they change their former direction; and when trees grow near a ditch, the roots which proceed in a direction that would necessarily bring them into the open air, instead of continuing this noxious progress, sink below the level of the ditch, then shoot across, and regain the soil on the opposite side. They turn from barren to fertile earth, which indicates something analagous to a choice of food.

"The mimosa or sensitive plant possesses the faculty of motion in an eminent degree. The slightest touch makes its leaves suddenly shrink, and together with the branch, bend down toward the earth. But the hedysarum movens, or moving plant, furnishes one of the most singular examples of vegetable motion. It is a native of the East Indies. Its movements are not excited by the contact of external bodies, but solely by the influence of the sun's rays. The motions of this plant are confined to the leaves; which move briskly in every direction when the sun shines. They move upward and downward; but sometimes turn almost round, twisting their foot-stalks. As long as the heat of the sun continues, these motions go on incessantly; but they cease during the night, and when the weather is cold and cloudy.

"The American plant, called dionca muscipula or

Venus's fly-trap, affords another instance of rapid vegetable motion. Its leaves are jointed and furnished with two rows of strong prickles. The surfaces of the leaves secrete a sweet liquor, which allures the approach of flies. When these parts are touched by the legs of a fly, the two lobes of the leaf instantly rise up, the rows of prickles lock themselves fast together, and squeeze the poor captive to death. A straw or pin will excite the same motions.

"Many leaves, as those of the mallow, follow the course of the sun. In the morning their upper surfaces are presented to the east; at noon to the south; and at sun-set to the west. During the night, or in rainy weather, their leaves are horizontal."

"The sleep of plants, as it has been called, affords another curious instance of vegetable motion. The leaves of many plants fold up during the night; but at the approach of the sun they expand. The modes of folding in the leaves are extremely various: but it is peculiarly worthy of attention, that they all dispose themselves so as to give the best protection to the young stems, flowers, buds, or fruit. For example, the leaves of the tamarind tree contract round the tender fruit, and protect it from the nocturnal cold. The cassia or senna, the glycine, and many of the papilionaceous plants, contract their leaves in a similar manner. The leaves of the chickweed, of the asclepias, atriplex, &c. are disposed in opposite pairs. During the night they rise perpendicularly, and join so close at the top, that they conceal the flowers.

The leaves of the sida or althea Theophrasti, of the ayenia, and anothera, are placed alternately. Though horizontal, or even depending during the day, at the approach of night they rise, embrace the stem, and protect the tender flowers.

"The leaves of the solanum or night shade, are horizontal during the day; but, in the night they rise and cover the flowers. The Egyptian vetch erects its leaves during the night, in such a manner that each pair seem to be one leaf only. The leaves of the white lupine, in the state of sleep, hang down and protect the young buds from being injured by the nocturnal air."

The flowers also, as well as the leaves, have the power of moving. During the night, many of them are inclosed in their calyx. Some, as of the German spurge, geranium striatum, and common whitlow grass, when asleep, hang their mouths toward the earth, to prevent the noxious effects of rain or dew. It is probable that such flowers are not defended by their leaves.

It would appear that this sleep of plants was designed for the perfection of the seed. For, those plants, the seed-receptacles of which are sufficiently secure, never sleep; and a plant after fructification sleeps no more.

The cause of these movements in plants has been ascribed to the presence or absence of the sun's rays. Some motions are evidently excited by heat. But plants kept in an equal temperature in a hot-house,

fail not to contract their leaves, or to sleep, in the same manner as when they are exposed to the open air. This fact evinces, that the sleep of plants is rather owing to a peculiar law, than to a quicker or slower motion of the juices.

All the facts I have enumerated on vegetable life, tend obviously to prove that plants are endowed with internal powers of self preservation quite independent of man, which watch over them continually, in a manner as incomprehensible, yet as efficient, as the instinctive actions of animals. And this power, for want of a better name, or a better knowledge of the cause, has been termed the principle of vegetation. But, in what manner the motions of plants just noticed differ from the motions which are thought to depend on a distinct principle belonging to a muscular fibre in animals, we are quite ignorant. It is hardly likely that the fibrous texture of plants and of their vessels, though possessed of elasticity, has any thing like the property of alternate contraction and relaxation known to exist in the true muscular fibre of animals; yet plants, as we have seen, are excited to very curious movements. So that in the infinitely wise economy of nature, similar effects may be accomplished by a different organization. Varied, however, as this may be, there is still something beyond which is inexplicable. We cannot doubt that the structure of leaves and flowers is as well adapted to the delicate stimuli acting upon them to excite their movements, such as light and heat, as the structure of animals is

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