In the fifth edition of the 'Origin,' my father altered a passage in the Historical Sketch (fourth edition page xviii.). He thus practically gave up the difficult task of understanding whether or no Sir R. Owen claims to have discovered the principle of Natural Selection. Adding, "As far as the mere enunciation of the principle of Natural Selection is concerned, it is quite immaterial whether or not Professor Owen preceded me, for both of us... were long ago preceded by Dr. Wells and Mr. Matthew." A somewhat severe critique on the fifth edition, by Mr. John Robertson, appeared in the "Athenaeum", August 14, 1869. The writer comments with some little bitterness on the success of the 'Origin:' "Attention is not acceptance. Many editions do not mean real success. The book has sold; the guess has been talked over; and the circulation and discussion sum up the significance of the editions." Mr. Robertson makes the true, but misleading statement: "Mr. Darwin prefaces his fifth English edition with an Essay, which he calls 'An Historical Sketch,' etc." As a matter of fact the Sketch appeared in the third edition in 1861. Mr. Robertson goes on to say that the Sketch ought to be called a collection of extracts anticipatory or corroborative of the hypothesis of Natural Selection. "For no account is given of any hostile opinions. The fact is very significant. This historical sketch thus resembles the histories of the reign of Louis XVIII., published after the Restoration, from which the Republic and the Empire, Robespierre and Buonaparte were omitted." The following letter to Prof. Victor Carus gives an idea of the character of the new edition of the 'Origin:'] CHARLES DARWIN TO VICTOR CARUS. Down, May 4, 1869. ... I have gone very carefully through the whole, trying to make some parts clearer, and adding a few discussions and facts of some importance. The new edition is only two pages at the end longer than the old; though in one part nine pages in advance, for I have condensed several parts and omitted some passages. The translation I fear will cause you a great deal of trouble; the alterations took me six weeks, besides correcting the press; you ought to make a special agreement with M. Koch [the publisher]. Many of the corrections are only a few words, but they have been made from the evidence on various points appearing to have become a little stronger or weaker. Thus I have been led to place somewhat more value on the definite and direct action of external conditions; to think the lapse of time, as measured by years, not quite so great as most geologists have thought; and to infer that single variations are of even less importance, in comparison with individual differences, than I formerly thought. I mention these points because I have been thus led to alter in many places A FEW WORDS; and unless you go through the whole new edition, one part will not agree with another, which would be a great blemish...