It is the more necessary to examine the various forms of this theory, because unquestionably it can appeal to not a few _natural analogies_, which may serve, on a superficial view, to give it the aspect of verisimilitude. For many of the most signal works of God have been manifestly framed on the principle of gradual growth, and matured by a process of progressive development. We see in the natural world a small seed deposited in the earth, which, under the agency of certain suitable influences, germinates and springs up, producing first a tender shoot, then a stem, and branches, and leaves, and blossoms, and fruit; and every herb or tree, "having seed in itself," makes provision for the repetition of the same process, and the perpetuation and indefinite increase of its kind. The same law is observed in the animal kingdom, where a continuous race is produced from a single pair. And even in the supernatural scheme of Revelation itself, the truth was gradually unfolded in a series of successive dispensations; the First Promise being the germ, which expanded as the Church advanced, until it reached its full development in the Scriptures of the New Testament. These and similar instances may suffice to show that, both in the natural and supernatural Providence of God, He has been pleased to act on the principle of _gradual and progressive_, as contradistinguished from that of _instant and perfect_ production; and they may seem, at first sight, to afford some natural analogies in favor of the radical idea on which the various modern Theories _of_ Development are based. In such circumstances it would be an unwise and dangerous course either to overlook the palpable facts which Nature and Revelation equally attest, or to deny that they may afford signal manifestations of the manifold wisdom of God. Nor is it necessary for any enlightened advocate of Theism to betake himself to these expedients; he may freely admit the existence of _such_ cases of gradual development, he may even appeal to them as illustrative of the order of Nature, and the design which that order displays; and the only question which he is at all concerned to discuss amounts in substance to this: Whether the method of production which is pursued in the _ordinary course_ of Nature can account for the _original commencement_ of the present system of things? But the state of the question, and the right application of the argument, may be best illustrated by considering each of the _four_ forms of the theory separately and in succession. SECTION I. THEORY OF _COSMICAL_ DEVELOPMENT, OR OF THE PRODUCTION OF WORLDS AND PLANETARY SYSTEMS BY NATURAL LAW.--"THE VESTIGES."