Mr. Chapman is more a disciple of Haeckel than of Darwin, and follows that gentleman in all his vagaries—a course well calculated to increase rather than decrease the amount of prejudice against what there may be of truth in Darwinism. Among the advocates of this, as of almost all theories, there are extremists. Our author seems to have gone to school to all of them, and swallowed all they told him, no matter how paradoxical, no matter how little proof to substantiate it. On the other hand, of all that has been said against pure Darwinism, not a word has been recorded by Mr. Chapman; and of those who, like Prof. Agassiz, do not agree with Mr. Darwin, or who, like St. George Mivart, have, as we think, dealt his theory blows from which it will not recover, he does not make the smallest mention. Yet it cannot be that Agassiz and Mivart are too small to be noticed by Mr. Chapman. Agassiz is too venerable a name in science to need any demonstration that his opinion on scientific matters is entitled to consideration. Mivart is, we take it, a younger man; yet, if he has not made himself an abiding reputation by what he has the modesty to call his “little book,” the _Genesis of Species_, he has made a name which must live, if Darwin’s, and Lyell’s, and Huxley’s do; since all these men have found in him a foe worthy of their steel—and the latter of the vials of his wrath. We would not consider this article complete without a condensed history of the controversy between Mr. Huxley and Mr. Mivart, occasioned by the publication by the latter of his admirable work, the _Genesis of Species_. We give it here for this, as well as for the reason that it will serve as the best general answer it is in our power to give to Mr. Chapman and other writers of his character. But first a few remarks on Darwin’s theory. It is only a theory, a mere hypothesis. Mr. Darwin does not pretend to have proved it himself; nor does his advocate, Mr. Huxley, who seems to have taken Mr. Darwin and the Darwinian theory under his special protection, pretend that it is proved. Bearing in mind that the Darwinian theory is only a hypothesis, we must estimate its value as we estimate that of other hypotheses, viz., by its ability to account for all the facts of which it pretends to be the solution. The Copernican system of astronomy, for instance, is only a hypothesis; yet, as there is no known astronomical fact absolutely contradictory to it, we accept it as true. If there were only one fact which it did not explain and could not explain; above all, if there were one fact at variance with the hypothesis, the hypothesis must give way, and the fact stand; for one fact is worth a thousand hypotheses, and one fact in cases of this kind, as Mr. Huxley says, as good as five hundred.