My dear Sir

On reflection I fear you will find it endless labour to give all author’s names in notes.² So use your own discretion; anyhow most ought to be introduced. You might omit the word “note” in the index,³ as the searcher has only one page to search; & even a word omitted in index is a gain.— When I had strength & made my own index, I used to give every author’s name, but added only 2 or 3 words on the subject on which he treated or species or genus treated of by him; but then I never had such an index to make as this ought to be.⁴ But as I said before kindly use your discretion & make a good Index.—

Yours very sincerely | C. Darwin