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Show 228 PHYSIOGNOMY OF PLANTS. animalculre, are carried up by the winds from the surface of evaporating waters. These minute creatures, motionless and apparently dead, are borne to and fro in the air until the falling dews bring them back to the surface of the earth, dissolve the film or envelop which encloses their transparent rotating bodies, (3) and, probably by means of the oxygen which all waters contain, breathe new irritability into their dormant organs. According to Ehrenberg's brilliant discovery, the yellow sand or dust which falls like rain on the Atlantic near the Cape de Verde Islands, and is occasionally carried even to Italy and Middle Europe, consists of a multitude of silicious-shelled microscopic animals. Perhaps many of them float for years in the upper strata of the atmosphere, until they are brought down by vertical currents or in accompaniment with the superior current of the trade-winds, still susceptible of revivification, and multiplying their species by spontaneous division in conformity with the particular laws of their organization. But, besides creatures fully formed, the atmosphere contains innumerable germs of future life, such as the eggs of insects and the seeds of plants, the latter provided with light hairy or feathery appendages, by means of which they are wafted through the air during long autumnal wanderings. Even the fertilizing dust or pollen from the anthers of the male flowers, in species in which the sexes are separated, is carried over land and sea, by winds and by the agency of winged insects, (4) to the solitary female plant on other shores. Thus, wherever the glance of the inquirer into Nature penetrates, he sees the continual dissemination of life, either fully formed or in the germ. If the aerial ocean in which we are submerged, and above the surface of which we cannot rise, be indispensable to the existence of organized beings, they also require a more substantial aliment, which they can find only at the bottom of this gaseous ocean. This bottom is of two kinds : the smaller portion consisting of dry land in immediate contact with the external atmosphere, and the larger portion consisting of water, which may perhaps have been formed thousands of years ago by electric agencies from gaseous substances, and which is now incessantly undergoing decomposition in the labor- |