From W. S. Dallas   10 November 1867

My dear Sir

I have to thank you for your two notes & will endeavour throughout the Index to select the references to authors as judiciously as possible.—¹ The principle I have followed hitherto is to give those whose positive statements are cited, omitting those only quoted in notes in support of statements in the text,—but as you wish the whole given I think it might be managed without very great difficulty by running through the sheets a second time before completing the Index—² I will look to this at the proper time.—

Believe me | Your’s very truly | W. S. Dallas.

C. Darwin Esq^r. F.R.S. | &c &c &c