There is a good reason why novels always end with the marriage of the hero and heroine: our interest is always more excited by the struggles, than by the results of victory. So long as the lovers are unhappy, or apart, and are eager to vanquish obstacles, our sympathy is active; but no sooner are they happy, than we begin to look elsewhere, for other strugglers on whom to bestow our interest. It is the same with biography. We follow the hero through the early years of struggle with intense interest, and as long as he remains unsuccessful, baffled by rivals or neglected by the world, we stand by him and want him to succeed; but the day after he is recognized by the world our sympathy begins to slacken. It is this which gives Cuvier’s _Letters to Pfaff_[8] their charm. I confess that, M. le Baron Cuvier, administrator, politician, academician, professor, dictator, has always had but a very tepid interest for me; probably because his career early became a continuous success, and Europe heaped rewards upon him; whereas, his unsuccessful rival, Geoffroy St. Hilaire, claims my sympathy to the close. If, however, M. le Baron is a somewhat dim figure in my biographical gallery, it is far otherwise with the youth Cuvier, as seen in his letters; and, as at this present moment there is nothing under our Microscope which can seduce us from the pleasant volume, suppose we let our “Studies” take a biographical direction. “Genius,” says Carlyle, “means transcendent capacity for taking trouble, first of all.” There are many young gentlemen devoutly persuaded of their own genius, and yet candidly avowing their imperfect capacity for taking trouble, who will vehemently protest against this doctrine. Without discussing it here, let us say that genius, or no genius, success of any value is only to be purchased by immense labour; and in science, assuredly, no one will expect success without first paying this price. In Cuvier’s history may be seen what “capacity for taking trouble” was required before his success could be achieved; and this gives these _Lettres à Pfaff_ a moral as well as an interest.