At the beginning of the year 1867 he was at work on the final chapter—“Concluding Remarks” of the ‘Variation of Animals and Plants under Domestication,’ which was begun after the rest of the MS. had been sent to the printers in the preceding December. With regard to the publication of the book he wrote to Mr. Murray, on January 3:—

“I cannot tell you how sorry I am to hear of the enormous size of my book I fear it can never pay. But I cannot shorten it now; nor, indeed, if I had foreseen its length, do I see which parts ought to have been omitted.

“If you are afraid to publish it, say so at once, I beg you, and I will consider your note as cancelled. If you think fit, get any one whose judgment you rely on, to look over some of the more legible chapters, namely, the Introduction, and on dogs and plants, the latter chapters being, in my opinion, the dullest in the book. … The list of chapters, and the inspection of a few here and there, would give a good judge a fair idea of the whole book. Pray do not publish blindly, as it would vex me all my life if I led you to heavy loss.”

Mr. Murray referred the MS. to a literary friend, and, in spite of a somewhat adverse opinion, willingly agreed to publish the book.