Whether the earth in its origin was a fragment thrown off from some exploded planet which had filled the measure of its destiny, or whether it arose from the gradual accretion of elementary substances diffused in infinite space, are questions which cannot be satisfactorily answered. Either method is not only plausible, but consistent with the known laws and operations of Nature. It seems quite probable that those erratic bodies known as comets are but incipient planets, which continue, as they revolve in their mystical flight, to accumulate gaseous matter until they have acquired and condensed a sufficient amount to become orbs, or worlds; when, by the influence of physical forces, they take their places in some one or other of the existing planetary systems. It is thus perhaps that the law of development constructs a world with as much ease as it constructs a grain of sand; nor can we doubt that the processes of aggregation and dissolution are made reciprocal in their relations, and perpetual in their action. In a philosophical sense, "life" and "death" are but conventional terms, meaning nothing more than a change of matter from one form of existence to another. Whatever changes may take place, matter can neither be increased nor diminished. Infinite space, being an immateriality, could never have been created and cannot therefore be limited or annihilated. In all probability it still is, and always has been, filled with the elements of matter,--too subtile, perhaps, to be perceived, yet destined in the course of eternal ages to be wrought and re-wrought into infinite varieties of corporeal existences, mineral, vegetal, and animal, ever progressing from the imperfect to the perfect. Thus Nature teaches us the lesson that in perfection dwells the central Life, the quickening power of the universe. In accordance with this view, we may regard every particle of matter in the universe as the germ of a world. And yet what are called original elements may be such, or may not. Supposed monads, or simple unities, if they exist at all, may be capable of analysis by the application of physical agencies or forces as yet unknown to science. Though science has disclosed much that is wonderful in the mechanism of Nature, there still lies before us an infinite unknown. Whether ultimately the human mind will become so enlarged and extended in its powers as to comprehend the infinite, admits of no positive assurance; yet in the unrevealed design of the great future, such may be the result.