Page:Scientific Memoirs, Vol. 1 (1837).djvu/248

236 fixing itself upon a given spot; while, on the other hand, locomotion is the characteristic of the animal kingdom. For there is no comparison between plants taking root, and the adhesion of some animals, corals, and oysters, to the ground by means of their shells. In the latter case there is not, as there is in that of the plant, an active dynamical intrusion into the maternal bosom of the earth for the sake of nourishment and life, but a mere mechanical hold of the surface. A fifth consequence is the more marked dependence of vegetable life on the life of the earth. Whether the vegetative organization awakes and develops itself, or sleeps and dies, depends accordingly on the position of the planet with respect to the sun and other heavenly bodies, as well as on the peculiar development of the soil. Though, these circumstances affect animal life also, it is not to be denied that they do so in a far inferior degree, and that the progress of animal organization imparts an independence of which the plant is utterly incapable. As the sixth and last consequence arising from the less perfect unity of the plant, we are to consider not only the dualism already mentioned, but the peculiar nature of every bud; and every internodium may be considered as a whole in itself, or in some measure an individual plant; wherefore a bush or a tree is more properly compared to an aggregate of animals (a coral bank) than to a single animal. In this way we shall easily comprehend the various modes of propagating plants, in which a bud (an eye) and the shoots that issue from it renew the parent organism, and that which we see in the bud is exhibited likewise as tubercles in the root or also (as in the genus Allium) near the flower, or as the bulb, and always possessing the power of reproducing the whole plant out of itself; nay the very seed is but an improved and more perfectly compact picture of the bud.

If we closely examine the structure and composition of plants, we find that, like the organism of the earth itself, they contain solid, fluid, and gaseous elementary particles. We see that in the plant, as well as in the earth, the fluid contributes to the formation of the solid parts, and that the finer and therefore more destructible organization of the plant is composed of chemical elements, namely, the carbonic, hydrogen, and oxygen gases. The transition of the fluids into solids, and consequently the history of the formation of the proper body of the plant itself, is evident in its primary structure, that is, in its cellular tissue. If we call to our recollection the history of the primitive formation of the rudiments of organic bodies in the green matter of Priestley, and see in this the conditions of this formation,—whilst, under the influence of light and gravitation, some particles of the original fluid attain the nature of individual beings, as well as a tendency to internal unity, and consequently a globular form,—it becomes clear that this development cannot occur without a separation of those particles from the rest, without an individual limitation in form of a spherical surface; so that the rudiment of