to stir up enquiry among the picked spirits of the scientific and philosophical coterie. Therein lies the true secret of his rapid, his brilliant, and his triumphant progress. He had found out not only _that_ it was so, but _how_ it was so, too. In Aristotelian phrase, he had discovered the _πῶς_ as well as the _ὅτι_. CHAPTER VIII. THE DESCENT OF MAN. In 1871, nearly twelve years after the 'Origin of Species,' Darwin published his 'Descent of Man.' We have seen already that he would fain have avoided the treatment of this difficult and dangerous topic a little longer, so as to let his main theory be fairly judged on its own merits, without the obtrusion of theological or personal feelings into so purely biological a question; but the current was too strong for him, and at last he yielded. On the one hand, the adversaries had drawn for themselves the conclusion of man's purely animal origin, and held it up to ridicule under false forms in the most absurd and odious light. On the other hand, imprudent allies had put forth under the evolutionary ægis their somewhat hypothetical and extravagant speculations on this involved subject, which Darwin was naturally anxious to correct and modify by his own more sober and guarded inferences. The result was the second great finishing work of the complete Darwinian system of things. Ever since evolutionism had begun to be at all it had been observed that a natural corollary from the doctrine of descent with modification was the belief in man's common ancestry with the anthropoid apes. As early as the middle of the last century, indeed, Lord Monboddo, a whimsical Scotch eccentric, had suggested in his famous book on the origin of language the idea that men were merely developed monkeys. But this crude and unorganised statement of a great truth, being ultimately based upon no distinct physical grounds, deserved scarcely to be classed higher than the childish evolutionism of 'Telliamed' De Maillet, which makes birds descend from flying-fish and men the offspring of the hypothetical tritons. On this point as on most others the earliest definite scientific views are those of Buffon, who ventured to hint with extreme caution the possibility of a common ancestry for man and all other vertebrate animals. Goethe the all-sided had caught a passing glimpse of the same profound conception about the date of the Reign of Terror; and Erasmus Darwin had openly announced it, though without much elaboration, in his precocious and premature 'Zoonomia.' Still more specifically, in a note to the 'Temple of Nature,' the English evolutionist says: 'It has been supposed by some that mankind were formerly quadrupeds.... These philosophers, with Buffon and Helvetius, seem to imagine that mankind arose from one family of monkeys on the banks of the Mediterranean;' and in the third canto of that fantastic poem, he enlarges upon the great part performed by the hand, with its opposable thumb, in the development