on slowly at my next book, and though I never am idle, I make but slow
progress; for I am often interrupted by being unwell, and my subject
of sexual selection has grown into a very large one. I have also had
to correct a new edition of my "Origin," (679/3. The 5th edition.), and
this has taken me six weeks, for science progresses at railroad speed.
I cannot tell you how rejoiced I am that your book is at last out; for
whether it sells largely or not, I am certain it will produce a great
effect on all capable judges, though these are few in number.

P.S.--I have just received your letter of January 12th. I am greatly
interested by what you say on Eschscholtzia; I wish your plants had
succeeded better. It seems pretty clear that the species is much more
self-sterile under the climate of Brazil than here, and this seems to me
an important result. (679/4. See Letter 677.) I have no spare seeds at
present, but will send for some from the nurseryman, which, though not
so good for our purpose, will be worth trying. I can send some of my own
in the autumn. You could simply cover up separately two or three single
plants, and see if they will seed without aid,--mine did abundantly.
Very many thanks for seeds of Oxalis: how I wish I had more strength and
time to carry on these experiments, but when I write in the morning, I
have hardly heart to do anything in the afternoon. Your grass is most
wonderful. You ought to send account to the "Bot. Zeitung." Could you
not ascertain whether the barbs are sensitive, and how soon they
become spiral in the bud? Your bird is, I have no doubt, the Molothrus
mentioned in my "Journal of Travels," page 52, as representing a North
American species, both with cuckoo-like habits. I know that seeds from
same spike transmitted to a certain extent their proper qualities; but
as far as I know, no one has hitherto shown how far this holds good, and
the fact is very interesting. The experiment would be well worth trying
with flowers bearing different numbers of petals. Your explanation
agrees beautifully with the hypothesis of pangenesis, and delights me.
If you try other cases, do draw up a paper on the subject of inheritance
of separate flowers for the "Bot. Zeitung" or some journal. Most men,
as far as my experience goes, are too ready to publish, but you seem
to enjoy making most interesting observations and discoveries, and are
sadly too slow in publishing.

LETTER 680. TO F. MULLER. Barmouth, Jul