From Charles Henry Binstead   17 April 1868

My dear Sir

I have had during the past few days the pleasure of reading your valuable & interesting book on “The Variation of Animals &c under domestication”—¹

—As an ornithologist in a very small way I have read with great interest your Chapter on Ducks &c   But I do not notice that you have observed a change that I fancy takes place in Mallards when becoming domesticated— it is this   that in the wild Duck the claws are black whereas in the tame ones they are white   I think I have noticed this in several cases & take the liberty of informing you—as it may have escaped your observation &—should there be anything in it & your book reaches a 2^nd Edition—it may be of service to you in rendering the same more complete.²

I have taken the liberty of forwarding you this letter through the hands of your publisher M^r. Murray.³

I am D^r Sir | Yours very faithfully | Chas. H. Binstead

The | Rev^d. C. Darwin M.d.