My Dear Sir,—

I thank you sincerely for your letter of March 22nd. Almost every word in it is of value to me, and you have proved yourself, as on so many other occasions, the most obliging of observers. I have heard from Dr Asa Gray that the worms do plenty of work in the U. States, so that now I think I may opinion that they work in much the same way in all parts of the world.²

I will specify a few of the points in which I should be very glad for further information. As before asked, do the very heavy rains fairly wash down the castings?³ I should be especially glad to hear if you can find any castings on a slope, whether they are washed in any perceptible degree from the slope by very heavy rain. Do the castings ever disintegrate into dust, at the commencement of the dry season, so that the casting could be blown away by the wind?

How deep down do you generally find worms? You have given me some information on this head.⁴ Do your worms draw leaves or little sticks into the mouths of their burrows, or pile pebbles over the mouths, as our worms are continually doing? It is astonishing to me that the worms can exist in the flooded rice fields. I did receive your paper on the sandalwood parasites, and read it with much interest.⁵ Pray do not trouble yourself to send the Lecosia, for as the wretch will not make perfect flowers, I care very little about it.⁶

I very sincerely wish all success to your great work, of which you send me the contents; it must be a very arduous undertaking.⁷ Once again I cordially thank you for your letter and observations, which are of real value to me.

Yours very sincerely, | Ch. Darwin.