1869.] FIFTH EDITION OF THE 'ORIGIN.' 109 



calls 'An Historical Sketch,' &c." As a matter of fact a 

 Sketch appeared in the third edition in 1 861. 



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 Cams gives an idea of 

 the character of the new edition of the ' Origin : '] 



C. Darwin to Victor Cams. 



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 varia- 

 tions are of even less importance, in comparison with indi- 

 vidual 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 



