successively introduced not only higher and higher forms and grades of intellect, but at a much remoter period may have cleared at one bound the space which separated the highest stage of the unprogressive intelligence of the inferior animals from the first and lowest form of improvable reason manifested by man.
To say that such leaps constitute no interruption to the ordinary course of nature, is more than we are warranted in affirming. In the case of the occasional birth of an individual of superior genius, there is certainly no break in the regular genealogical succession; and when all the mists of mythological fiction are dispelled by historical criticism, when it is acknowledged that the earth did not tremble at the nativity of the gifted infant, and that the face of heaven was not full of fiery shapes, still a mighty mystery remains unexplained, and it is the order of the phenomena, and not their cause, which we are able to refer to the usual course of nature.
Dr. Asa Gray, in the excellent essay already cited (p. 502), has pointed out that there is no tendency in the doctrine of Variation and Natural Selection to weaken the foundations of Natural Theology; for, consistently with the derivative hypothesis of species, we may hold any of the popular views respecting the manner in which the changes of the natural world are brought about. We may imagine 'that events and operations in general go on in virtue simply of forces communicated at the first, and without any subsequent interference, or we may hold that now and then, and only now and then, there is a direct interposition of the Deity; or, lastly, we may suppose that all the changes are carried on by the immediate orderly and constant, however infinitely diversified, action of the intelligent, efficient Cause.' They who maintain that the origin of an individual, as well as the origin of a species or
