There have been various applications of the general principle of Development, by means of which an attempt has been made to explain the origin of all things by Natural Laws, so as to exclude the necessity of any Divine interposition, either for the creation of the world, or for the introduction and establishment of Christianity itself. It has been applied, first, to explain the origin of worlds and planetary systems, by showing that, certain specified conditions being presupposed, there are fixed mechanical laws which might sufficiently account for the production of the earth and of the other planets and satellites of our Solar System, without any special interposition of Divine power at the commencement of the existing order of things. It has been applied, secondly, to explain the origin of the various tribes or races of vegetable and animal life, and especially the production of the human race, by showing that the existing types may have sprung, by a process of gradual development, from inferior races previously existing, and that these again may have been produced by the action of chemical agents in certain favorable conditions. It has been applied, thirdly, to explain all the most important phenomena of Human History, and to illustrate the law which is supposed to determine and regulate the progressive course of civilization, so as to account, on natural principles, for the origin and prevalence of the various forms of Religion, and even for the introduction, in its appointed season, of Christianity itself, without having recourse to anything so utterly unphilosophical as the idea of a Divine Revelation, or the supposition of supernatural agency. And it has been applied, fourthly, to explain the order, and to vindicate the use, of those additions both to the doctrines and rites of primitive Christianity, which Protestants have denounced as _corruptions_, but which Popish and Tractarian writers defend as _developments_, of the system that was originally deposited, like a prolific germ or seed, in the bosom of the Catholic Church.