To F. T. Köppen 28 April 1
Down. | Beckenham | Kent. S.E.
I am greatly indebted to you for your valuable present of your Heuschrecken in Südrussland & for your interesting letter.2 I have no doubt I shall find much matter of value to me in your volume; but unfortunately I am a poor German scholar & read the language with much difficulty, which has been an irreparable loss to me.— The facts which you mention in your letter in relation to the increase of mice &c from the invasion of the grasshoppers are very curious; & it is a subject which always possesses a special interest for me.3
With much respect & my best thanks, I remain | Dear Sir | Yours faithfully | Ch. Darwin
Thanks for FTK’s locust paper ["Die geographische Verbreitung der Wanderheuschrecke", Petermann’s Geogr. Mittheil. (1871)].
Please cite as
Darwin Correspondence Project, “Letter no. 7723,” accessed on 10 December 2016, http://www.darwinproject.ac.uk/DCP-LETT-7723