To J. V. Carus   4 May 1869

My dear Sir

I am pleased to hear about the Origin, for I am now completing a new edit., which will be published in a month’s time or less.¹ I have gone very carefully thro’ the whole, trying to make some parts clearer, & adding a few discussions & facts of some importance. The new ed. is only 2 pages, at the end, longer than the old; though in one part 9 pages in advance, for I have condensed several parts, & omitted some passages. The translation, I fear will cause you a good deal of trouble; the alterations took me 6 weeks, besides correcting the press; you ought to make a special agreement with M. Koch.² 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.³

Thus I have been led to place somewhat more value on the direct & definite action of external conditions,—to think the lapse of time as measured by years not quite so great as most geologists have thought,—& to infer that single variations are of even less importance, in comparison with individual differences, than I formerly thought.⁴ I mention these points because I have been thus led to alter in many places a few words; & unless you go thro’ the whole new edition, one part will not agree with another, which w^d be a great blemish. I c^d lend you the corrected sheets, which w^d shew where changes had been made, but then some corrections have been added in the proofs, which w^d not appear in the above sheets. Please sometime to inform me whether you wish for the loan of the corrected sheets, & whether you w^d like a bound copy, or clean loose sheets for y^r translation.

I am pleased to hear about the sale of “Domestic Animals,”⁵ Altho’ I am never idle my new book makes very slow progress; & I will assuredly inform you as soon as it goes to the printers.⁶

Believe me | my dear Sir | yours very sincerely | Charles Darwin