ghly you appreciate (and I do not think that
this is general with the men of science) H. Spencer; I suspect that
hereafter he will be looked at as by far the greatest living philosopher
in England; perhaps equal to any that have lived. But I have no
business to trouble you with my notions. With sincere thanks for the
interest which your work has given me, I remain, yours very faithfully,

CH. DARWIN.

FROM A LETTER TO J.D. HOOKER

CLIFF COTTAGE, BOURNEMOUTH, September 26th, 1862.

_My Dear Hooker:_

Do not read this till you have leisure. If that blessed moment ever
comes, I should be very glad to have your opinion on the subject of this
letter. I am led to the opinion that Drosera must have diffused matter
in organic connection, closely analogous to the nervous matter of
animals. When the glans of one of the papillae or tentacles in its
natural position is supplied with nitrogenized fluid and certain other
stimulants, or when loaded with an extremely slight weight, or when
struck several times with a needle, the pedicel bends near its base in
under one minute. These varied stimulants are conveyed down the pedicel
by some means; it cannot be vibration, for drops of fluid put on quite
quietly cause the movement; it cannot be absorption of the fluid from
cell to cell, for I can see the rate of absorption, which, though quick,
is far slower, and in Dionaea the transmission is instantaneous; analogy
from animals would point to transmission through nervous matter.
Reflecting on the rapid power of absorption in the glans, the extreme
sensibility of the whole organ, and the conspicuous movement caused by
varied stimulants, I have tried a number of substances which are not
caustic or corrosive, ... but most of which are known to have a
remarkable action on the nervous matter of animals. You will see the
results in the inclosed paper. As the nervous matter of different
animals is differently acted on by the same poisons, one would not
expect the same action on plants and animals; only, if plants have
diffused nervous matter, some degree of analogous action. And this is
partially the case. Considering these experiments, together with the
previously made remarks on the functions of the parts, I cannot avoid
the conclusion that Drosera possesses matter at least in some degree
analogous in constitution and function to nervous matter. Now do tell me
what you think, as far as you can judge from my abstract. Of co