k.)

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