om
injury from warm rain.

3. The axis, the main petiole, and the terminal leaflets are all,
when the temperature is high, in constant movement, just like that of
climbing plants. This movement seems to be of no service, any more than
the incessant movement of amoeboid bodies. The movement of the terminal
leaflets, though insensible to the eye, is exactly the same as that of
the little lateral leaflets--viz. from side to side, up and down,
and half round their own axes. The only difference is that the little
leaflets move to a much greater extent, and perhaps more rapidly; and
they are excited into movement by warm water, which is not the case with
the terminal leaflet. Why the little leaflets, which are rudimentary in
size and have lost their sleep-movements and their movements from
being shaken, should not only have retained, but have their spontaneous
movements exaggerated, I cannot conceive. It is hardly credible that
it is a case of compensation. All this makes me very anxious to examine
some plant (if possible one of the Leguminosae) with either the terminal
or lateral leaflets greatly reduced in size, in comparison with the
other leaflets on the same leaf. Can you or any of your colleagues think
of any such plant? It is indirectly on this account that I so much want
the seeds of Lathyrus nissolia.

I hear from Frank that you think that the absence of both lateral
leaflets, or of one alone, is due to their having dropped off; I thought
so at first, and examined extremely young leaves from the tips of the
shoots, and some of them presented the same characters. Some appearances
make me think that they abort by becoming confluent with the main
petiole.

I hear also that you doubt about the little leaflets ever standing not
opposite to each other: pray look at the enclosed old leaf which
has been for a time in spirits, and can you call the little leaflets
opposite? I have seen many such cases on both my plants, though few so
well marked.

LETTER 719. TO J.D. HOOKER. Down, October 23rd [1873].

How good you have been about the plants; but indeed I did not intend
you to write about Drosophyllum, though I shall be very glad to have
a specimen. Experiments on other plants lead to fresh experiments.
Neptunia is evidently a hopeless case. I shall be very glad of the other
plants whenever they are ready. I constantly fear that I shall become to
you a giant of bores.

I am delighted to hear that you are at work on N