To J. V. Carus   23 March 1881

My dear Sir

The serious error at p. 503, I feel nearly sure from memory consists in my having written “quicker” for “slower”.¹ My mass of notes is so gigantic that it would take me days to find the original observations. With respect to the apparent error on p. 111. I remember thinking that I might puzzle some one by it, but stupidly did not explain the apparent contradiction; I trusted to the words “some of the species”,, but I ought to have added some such sentence—as “this makes 27 genera, but in Oxalis the cotyledons of some species rise & those of others fall at night, so that this genus is here counted twice”.²

Many thanks for the other errata.—

I am greatly pleased that you approve of our book, as I suppose that it will be the last of any size which I shall publish.

I shall, however, send in 3 or 4 weeks the M.S. of a quite small book of little moment to the Printers.³ The title will be,

“The Formation of Vegetable Mould

Through the action of Worms

with observations on their habits.

by

C. Darwin”

You have been a very wicked man not to tell me how your health is.—⁴ My health is certainly better than it was, but I have little strength & feel very old.—

Believe me, my dear Sir | Yours sincerely | Charles Darwin