My dear Sir

I am vexed to the heart that you should have occasion to write to me again about this Index.—¹ I cannot plead illness, although as I am suffering again from the same pain in the back that laid me up in the summer, no doubt this has impeded my work, but the real cause of delay lies in the nature of the work itself.² I have, as I told M^r. Murray³ in a note written today, consumed more than half a ream of paper in writing out the analysis of the book.— This part of the business is now completed, however, & the slips are in process of being cut up & sorted,—I shall have a considerable portion in the printer’s Hands on Monday morning.—⁴

It is now many weeks since I have left off work until at least between 1 & 2 oclock in the morning, but very frequently, either through being utterly worn out, or from some other cause, I have not got through more than a sheet or sheet & a half of your book in 3 or 4 hours.—⁵ This, I hope is the last letter of this kind I shall have to write—⁶

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

C. Darwin Esq^r