[Enclosure]⁷

The foregoing article was published a year before the appearance of Mr. Darwin’s remarkable work on the ‘Origin of Species’. Whatever be thought of some of the conclusions at which Mr. Darwin has arrived, the value of his work as a contribution to the Natural History sciences, and as a guide to their future successful pursuit, cannot be too highly estimated. Nor is it possible to speak too strongly of the candid spirit manifest throughout this volume; leading its author to anticipate objections and acknowledge all difficulties; and to state, even perhaps beyond his own belief in them, the conclusions to which his doctrine might be liable, if carried to its extreme inferences.

Thinking it well that the argument on the other side should be fully and fairly weighed, I have made only a few very slight alterations in the article now reprinted; one of these referring to the changes in the animal world due to the principle of natural selection, operating amidst the general struggle for existence. This principle, which Mr. Darwin has so largely and effectively used in his researches, may be considered in great degree a new path of inquiry; and one which, steadily pursued by exact and patient observation, cannot fail of conducting to important results. It is certain that at some future time a revision and reform will be required of all existing catalogues of genera and species. How far the needful curtailment may carry us is yet doubtful; but there is reason to presume that it will stop very far short of anything like unity of origin, even with unlimited concession of time for the process and progress of change. An original act of creation, in time and under design, being assumed in every hypothesis, the conception of any primordial unity, capable of evolving and multiplying itself into all the actual forms of life, is infinitely more difficult than that of many distinct primitive forms, brought into simultaneous or successive existence by one designing and creating Power. Numbers, in truth (and this must ever be kept in mind), admit of no line or limitation, when applied to problems which pass so far beyond all human comprehension. Like in this to Time, similarly applied, their only boundary becomes that of Infinity.