animal life appears to be a hollow globular body. Consequently when the effort to attain a higher unity or a more perfect organization presses several of these globuli, possessing solid though weak surfaces, one toward the other, the surfaces, by mutual pressure, are necessarily modified into different geometrical angular bodies[1]. In the most imperfect plants we observe, as a consequence of an imperfectly developed internal structure, that in their single cells, which press each other but slightly, the globular form prevails, although on account of the linear direction peculiar to plants (see p. 235) it is elongated into the'ellipsoid; while in the more perfect plants, on the contrary, the single cells of their tissue appear, in consequence of the mutual pressure, in the form of regular dodecahedrons. Looking upon the cellular formation as the basis of the whole plant, and considering that the plant itself in its primitive destination is dependent on its relation to the planet and its unity (gravitation), we are fully entitled to identify the anatomical system of the cellular tissue[2], as the proper reproductive system of the plant, with terrestrial gravitation and the planetary body itself, inasmuch as that principle may be considered the basis of the whole organism of the earth. But since, in the organism of the earth, light and air, as constituting a second integrant part, stand opposed to gravitation [der Nachtseite], and since the plant bears a relation not only to gravitation but to light also (see p. 235) when its formation is complete, it will necessarily present a second anatomical system, namely that of the spiral vessels, which have been very justly considered of late as the organs that perform in plants the functions of nerves. The lower plants, which want no light for their development, are not provided with spiral vessels; in the more perfect plants, on the contrary, the spiral vessels are as essential a part of the organization as the cellular tissue. In fine, between both these systems of the cellular tissue and the spiral vessels (the earth and water system, and the light and air system, as they are called by Kieser[3],) the epidermis stands as a binding and connecting member, whose vessels appear to be the more perfect intercellular ducts, and its pores the orifices of these vessels[4].
As the anatomical systems of plants are therefore but very few, the multiplicity of their external organs, which unfolds itself in the most beautiful progression and regularity, is so much the more important. Whilst the root, penetrating more deeply in the direction of the earth, spreads itself with uniformity, the plant elevates itself more and more into the light, and attains a more delicate and perfect organization; in which process it is a fact deserving most particular attention, that this perfectibility does not manifest itself in the production of new organs
