I have [in the French edition] alluded to your work, which will also be published in English, as you will see in my paper, and which I will send you. (680/5. "Notes on the Fertilisation of Orchids." "Ann. Mag. Nat. Hist." 1869, Volume IV., page 141. The paper gives an English version of the notes prepared for the French edition of the Orchid book.)
P.S.--By an odd chance, since I wrote the beginning of this letter, I have received one from Dr. Hooker, who has been reading "Fur Darwin": he finds that he has not knowledge enough for the first part; but says that Chapters X. and XI. "strike me as remarkably good." He is also particularly struck with one of your highly suggestive remarks in the note to page 119. Assuredly all who read your book will greatly profit by it, and I rejoice that it has appeared in English.
LETTER 681. TO F. MULLER. Down, December 1st [1869].
I am much obliged for your letter of October 18th, with the curious account of Abutilon, and for the seeds. A friend of mine, Mr. Farrer, has lately been studying the fertilisation of Passiflora (681/1. See Letters 701 and 704.), and concluded from the curiously crooked passage into the nectary that it could not be fertilised by humming-birds; but that Tacsonia was thus fertilised. Therefore I sent him the passage from your letter, and I enclose a copy of his answer. If you are inclined to gratify him by making a few observations on this subject I shall be much obliged, and will send them on to him. I enclose a copy of my rough notes on your Eschscholtzia, as you might like to see them. Somebody has sent me from Germany two papers by you, one with a most curious account of Alisma (681/2. See Letter 672.), and the other on crustaceans. Your observations on the branchiae and heart have interested me extremely.
Alex. Agassiz has just paid me a visit with his wife. He has been in England two or three months, and is now going to tour over the Continent to see all the zoologists. We liked him very much. He is a great admirer of yours, and he tells me that your correspondence and book first made him believe in evolution. This must have been a great blow to his father, who, as he tells me, is very well, and so vigorous that he can work twice as long as he (the son) can.
Dr. Meyer has sent me his translation of Wallace's "Malay Archipelago," which is a valuable work; and as I have no use for the translation, I will this day forward it to you by post, but, to save postage, via England.
LETTER 682. TO F. MULLER. Down, May 12th [1870].
I thank you for your two letters of December 15th and March 29th, both abounding with curious facts. I have been particularly glad to hear in your last about the Eschscholtzia (682/1. See Letter 677.); for I am now rearing crossed and self-fertilised plants, in antagonism to each other, from your semi-sterile plants so that I may compare this comparative growth with that of the offspring of English fertile plants. I have forwarded your postscript about Passiflora, with the seeds, to Mr. Farrer, who I am sure will be greatly obliged to you; the turning up of the pendant flower plainly indicates some adaptation. When I next go to London I will take up the specimens of butterflies, and show them to Mr. Butler, of the British Museum, who is a learned lepidopterist and interested on the subject. This reminds me to ask you whether you received my letter [asking] about the ticking butterfly, described at page 33 of my "Journal of Researches"; viz., whether the sound is in anyway sexual? Perhaps the species does not inhabit your island. (682/2. Papilio feronia, a Brazilian species capable of making "a clicking noise, similar to that produced by a toothed wheel passing under a spring catch."--"Journal," 1879, page 34.)
The case described in your last letter of the trimorphic monocotyledon Pontederia is grand. (682/3. This case interested Darwin as the only instance of heterostylism in Monocotyledons. See "Forms of Flowers," Edition II., page 183.