His success was, no doubt, in great measure due to the fact that he knew our little ways, and humoured them; but if he had not had little ways of his own, he never could have been so much _au fait_ with ours. He knew, for example, we should be pleased to hear that he had taken his boots off so as not to disturb his worms when watching them by night, so he told us of this, and we were delighted. He knew we should like his using the word “sag,” so he used it, {245a} and we said it was beautiful. True, he used it wrongly, for he was writing about tesselated pavement, and builders assure me that “sag” is a word which applies to timber only, but this is not to the point; the point was, that Mr. Darwin should have used a word that we did not understand; this showed that he had a vast fund of knowledge at his command about all sorts of practical details with which he might have well been unacquainted. We do not deal the same measure to man and to the lower animals in the matter of intelligence; the less we understand these last, the less, we say, not we, but they can understand; whereas the less we can understand a man, the more intelligent we are apt to think him. No one should neglect by-play of this description; if I live to be strong enough to carry it through, I mean to play “cambre,” and I shall spell it “camber.” I wonder Mr. Darwin never abused this word. Laugh at him, however, as we may for having said “sag,” if he had not been the kind of man to know the value of these little hits, neither would he have been the kind of man to persuade us into first tolerating, and then cordially accepting, descent with modification. There is a correlation of mental as well as of physical growth, and we could not probably have had one set of Mr. Darwin’s qualities without the other. If he had been more faultless, he might have written better books, but we should have listened worse. A book’s prosperity is like a jest’s—in the ear of him that hears it.