To say that these laws, distinct and invariable as far as the observation of man has extended, may possibly have been superseded in the lapse of ages by a higher principle, manifesting itself only at long intervals, is again to have recourse to a blank hypothesis, incapable alike of proof or disproof, and unsupported by the faintest intimations from the world of experience. To build up a theory in this way is not to account for the work of creation by the natural agencies and inherent qualities of matter, _as at present observable_, but to fly off to the wild supposition, that matter and life were more richly endowed ages ago than they are in our own day. You affirm, that this higher principle of development did not override the inferior laws at the earlier periods in time's history, because, in the infancy of the universe, the conditions were wanting which are requisite for its manifestation,--because the earth was not ready, the atmosphere was not purified, for the nobler races of being. Very well; but these conditions are answered _now_. All things are ready at the present day for the innate energies of matter to put forth their utmost strength. Why do not fishes generate reptiles, and birds produce mammifers, _now_? Ah! but "the earth being now supplied with both kinds of tenants in great abundance, we could only expect to find the life-originating power at work in some very special and extraordinary circumstances." It seems, then, that these inherent qualities of matter, once supposed to be blind, absolute, and invariable in their operation, are really very judicious and reasonable; they suit the supply to the demand, and actually cease working when the market is likely to be overstocked. The results of such "_natural_ agencies" as these are very like the effects produced by the volitions of a wise and thinking being.