Lippstadt
9 Octobr. 1871.
My dear Sir
After having observed during the last four summers the insects fertilising our flowers and having studied these flowers themselves I am now about to lay down my observations in a work on fertilisation of flowers by insects.1 In order to make this work more useful for those who wish to find quickly what observations hitherto have been on cross-fertilisation of some plant, I intend to give a complet systematical list of all plants on which such observations have been made with short mention of the works in which this observations are published. I possess and know on this matter only the work of Sprengel, yours, those of Hildebrand, Delpino and Severin Axell.2 I would be much obliged to you, if you would acquaint me with those English and other works and Journals, in which you know that observations on cross-fertilisation (or on contrivances of flowers by which cross fertilisation is favoured) are published.
A memoir of mine “On the application of the Darwinian theory on bees” is now under press. As soon as I receive Separata, I will you send one3
I remain, my dear Sir, | yours very sincerely | H. Müller.
Please cite as “DCP-LETT-7997,” in Ɛpsilon: The Charles Darwin Collection accessed on