the information about the
earthworms. I suppose the soil in your forests is very loose, for in
ground which has lately been dug in England the worms do not come to the
surface, but deposit their castings in the midst of the loose soil.

I have some grand plants (and I formerly sent seeds to Kew) of the
cleistogamic grass, but they show no signs of producing flowers of any
kind as yet. Your case of the panicle with open flowers being sterile
is parallel to that of Leersia oryzoides. I have always fancied that
cross-fertilisation would perhaps make such panicles fertile. (686/1.
The meaning of this sentence is somewhat obscure. Darwin apparently
implies that the perfect flowers, borne on the panicles which
occasionally emerge from the sheath, might be fertile if pollinated from
another individual. See "Forms of Flowers," page 334.)

I am working away as hard as I can at all the multifarious kinds of
movements of plants, and am trying to reduce them to some simple rules,
but whether I shall succeed I do not know.

I have sent the curious lepidopteron case to Mr. Meldola.

LETTER 687. F. MULLER TO CHARLES DARWIN.

(687/1. In November, 1880, on receipt of an account of a flood in Brazil
from which Fritz Muller had barely escaped with his life ("Life and
Letters," III., 242); Darwin immediately wrote to Hermann Muller begging
to be allowed to help in making good any loss in books or scientific
instruments that his brother had sustained. It is this offer of help
that is referred to in the first paragraph of the following letter:
Darwin repeats the offer in Letter 690.)

Blumenau, Sa Catharina, Brazil, January 9th, 1881.

I do not know how to express [to] you my deep heartfelt gratitude for
the generous offer which you made to my brother on hearing of the
late dreadful flood of the Itajahy. From you, dear sir, I should have
accepted assistance without hesitation if I had been in need of it; but
fortunately, though we had to leave our house for more than a week, and
on returning found it badly damaged, my losses have not been very great.

I must thank you also for your wonderful book on the movements of
plants, which arrived here on New Year's Day. I think nobody else will
have been delighted more than I was with the results which you have
arrived at by so many admirably conducted experiments and observations;
since I observed the spontaneous revolving movement of Alisma I had seen
similar movements in so many and so d