Darwin was of course quite conscious of his growing triumph. Even hostility, animosity, execration, painful as they might be, afforded evidence of power and achievement. And he would not have been human, had he not relished the varied testimony of respect and admiration which came to him from every quarter. His natural distrust of himself was so great that it was hard for him to believe in success, even when it came, and before it came, he deprecated any attempt to discount it: ‘Please do not say to any one that I thought my book on Species would be fairly popular, and have a fairly remunerative sale (which was the height of my ambition), for if it prove a dead failure, it would make me the more ridiculous.’[381] Yet, however one might shrink and distrust oneself, to enter a great scientific meeting and have every one present rise to do one honor was undeniably agreeable. And, with his unfailing frankness, Darwin admits that praise was pleasant, and one could not have too much of it, provided one felt that it was in a measure deserved: ‘You pay me a superb compliment, and as I have just said to my wife, I think my friends must perceive that I like praise, they give me such hearty doses.’[382] Also, with equal frankness, he makes it plain in his autobiographical sketch that he realizes how great the success was and that it implied a certain prospect of permanence: ‘My books have sold largely in England, have been translated into many languages, and passed through several editions in foreign countries. I have heard it said that the success of a work abroad is the best test of its enduring value. I doubt whether this is at all trustworthy; but judged by this standard my name ought to last for a few years.’[383] When he died, he was unquestionably rated as one of the very first, if not the first, among the scientific men of his time. And it is equally unquestionable that his reputation has rather increased than diminished ever since. ‘“Before and after Darwin” will always be the _ante et post urbem conditam_ of biological history,’ says Professor Osborn.[384] Naturally Darwin’s theories have been criticized and attacked and largely modified by later investigations and discoveries. To Darwin himself variation, as the basis of natural selection, was the difficult, inexplicable point, and the experiments of Mendel, the mutation theory of De Vries, and many other lines of research have put the subject of variation in a new light. Natural Selection has been and will be the subject of controversy, both as to its working and as to the extent of its efficacy. Darwin’s inimitable caution left the way open for all these investigations, as is so well indicated in the excellent sentence of Professor Whitehead: ‘Darwin’s own writings are for all time a model of refusal to go beyond the direct evidence and of careful retention of every possible hypothesis.’[385]