much previous training and discipline, through the instrumentality of patriarchs, prophets, and legislators. One of the most striking proofs, in short, of the Divine wisdom in the dispensation of grace, is its harmonizing so exactly with the established course of nature. This is manifested more especially in the manner in which the heavenly blessings with which it is fraught have been communicated—slowly, gradually, and partially at first, more fully and generally diffused as men were prepared to receive them, and, when “the fullness of the time” had arrived, imparted freely and in the richest abundance unto all; light after light, truth after truth, and mercy upon mercy, all in such order of succession, that the former illustrate and recommend the latter, while the last are only a preparation for future and still greater mercies. And so it has been with the whole Course of Creation—the succession of strata, of animal and vegetable tribes, and with man and the adaptive provision for his higher destiny. This is a doctrine of development and of progression, widely different from that of the “Vestiges,” more in unison with the Creator’s wisdom and the Creator’s care:—a speculation worthy of a separate treatise, namely, the progress and development of man’s intelligent, moral, and spiritual being as indicated in THE COURSE OF REVELATION. CHAPTER IV. CAUSES OF EXTINCTION OF ORGANIC LIFE. When the palæontologist has completely established his position, that all the organic phenomena of primeval times have resulted from the impress of original structure, in opposition to the theory of progressive development and transmutation of species; and when he can trace, also, corresponding changes in the mineral formations in which the fossil remains are imbedded, the important inquiry has still to be made into the causes of the extinction of so many races of the animal and vegetable kingdoms. Introduced successively upon the surface of the earth, was there always a physical and necessary relation betwixt the living tribes and the varying conditions of the surrounding media in which their lot was cast? And do the differences in the one explain the changes in the organic functions of the other?