CHARLES DARWIN TO W.D. FOX. Down, May 7th [1855].
My dear Fox,
My correspondence has cost you a deal of trouble, though this note will not. I found yours on my return home on Saturday after a week's work in London. Whilst there I saw Yarrell, who told me he had carefully examined all points in the Call Duck, and did not feel any doubt about it being specifically identical, and that it had crossed freely with common varieties in St. James's Park. I should therefore be very glad for a seven-days' duckling and for one of the old birds, should one ever die a natural death. Yarrell told me that Sabine had collected forty varieties of the common duck!...Well, to return to business; nobody, I am sure, could fix better for me than you the characteristic age of little chickens; with respect to skeletons, I have feared it would be impossible to make them, but I suppose I shall be able to measure limbs, etc., by feeling the joints. What you say about old cocks just confirms what I thought, and I will make my skeletons of old cocks. Should an