To Asa Gray 15 January 1872
Down | Beckenham | Kent
Jan. 15— ’72
My dear Gray,
I have taken up an old subject which formerly interested me, namely the amount of earth brought to the surface by worms.1
I want to know whether you have in the States the little vermiform piles of earth which are so common on our lawns fields woods & waste lands.— Are they as numerous with you as they are with us?
I should have assumed that this would naturally be the case had it not occurred to me that the severe winters might make all the difference.—
A very few lines in answer would suffice.— It just occurs to me that if you had any correspondent in the Northern parts of Canada you might send this letter to him and thus get me some additional information on the subject.— Overworked as you are I hope you will forgive me for troubling you. Many thanks for Agassiz’s letter which from the handwriting I infer you sent me.—2
Pray give our very kind remembrances to Mrs Gray3 and | Believe me | Yours very sincerely | Ch. Darwin
Questions AG on earthworm activity in North America and would welcome information from northern Canada if AG has a correspondent there.