Page:Scientific Memoirs, Vol. 1 (1837).djvu/252

 

leaves and flowers being particularly capable of secretion and expiration, but less fit for absorption. Polarity is therefore the cause which brings the sap into motion by reciprocal attraction and repulsion from the root to the leaves and flowers, and from the leaves and flowers again to the root: a motion on which, moreover, the physical powers—which, as the condition of both these parts, we have named vegetative poles, namely the powers of light and gravitation—must have a most decided influence; since, for instance, it is a well-known fact, that the perspiration of plants is very different according to the degrees in which they are exposed or withdrawn from the light of the sun. But besides those active properties which contribute to the organic formation of plants, some of them possess a peculiar mobility, which seems to arise from real sensibility, and at the first glance presents a perfect line of demarcation between the vegetable and inorganic bodies. In order to have a clear insight into this fact, it is necessary to fix our idea of the word sensibility, as that which we would be understood to convey most correctly, if we say that it consists in the change operated by outward or inward circumstances in the feelings of a being conscious that it exists as a unity; consequently if we deny sensibility to the stone or the mineral, it is not because such a body is not subject to the most various agitations and changes, but because it is merely a member of a higher unity, and in itself is to be considered as an individual, not as a true unity. In regard to the plant we may say that it has become an organic unity; but on account of the dualism (see p. 235.) prevailing in its totality, and its being therefore bound as it were to the external world, we may with safety deny that it is conscious of its own unity; for in order to have self-consciousness, or an internal perception of unity, there must be, not merely that ideal unity which belongs to organized beings in general, but that real manifestation of unity which arises from the continual action and reaction of all the organs and an organic centre. But such action and reaction are not to be found in the plant, in which each bud may be considered as a whole; so that this real unity, as we shall hereafter see, is possible only in the animal, in which the organs are connected with a unity by means of the vascular and nervous systems. But if we cannot suppose plants to be possessed of sensibility, how can we account for their movements towards the light, the shrinking of the sensitive plant from the touch, the closing of the Dionæa by mechanical irritation, or the inclining of the stamina towards the stigma, and the regular embracing of extraneous bodies, and in definite directions, by the creeping plants, &c.? In our opinion all these phænomena are to be accounted for in the same way as the rotation of the earth, the motion of falling bodies, the oscillation of the sea in its ebbing and flowing, the attraction and repulsion of the cork balls in the electrometer; that is to say, we think that they are entirely the effects of external disposing causes, and therefore the consequence