After reading the above we feel that nothing more satisfactory could be desired. We are sure that we are in the hands of one who can indeed tell us “how the innumerable species inhabiting this world have been modified,” and we are no less sure that though others may have written upon the subject before, there has been, as yet, no satisfactory explanation put forward of the grand principle upon which modification has proceeded. Then follows a delightful volume, with facts upon facts concerning animals, all showing that species is due to successive small modifications accumulated in the course of nature. But one cannot suppose that Lamarck ever doubted this; for he can never have meant to say, that a low form of life made itself into an elephant at one or two great bounds; and if he did not mean this, he must have meant that it made itself into an elephant through the accumulation of small successive modifications; these, he must have seen, were capable of accumulation in the scheme of nature, though he may not have dwelt on the manner in which this is accomplished, inasmuch as it is obviously a matter of secondary importance in comparison with the origin of the variations themselves. We believe, however, throughout Mr. Darwin’s book, that we are being told what we expected to be told; and so convinced are we, by the facts adduced, that in some way or other evolution must be true, and so grateful are we for being allowed to think this, that we put down the volume without perceiving that, whereas Lamarck _did_ adduce a great and general cause of variation, the insufficiency of which, in spite of errors of detail, has yet to be shown, Mr. Darwin’s main cause of variation resolves itself into a confession of ignorance.