movement. It should rather be said that plants
acquire and display this power only when it is of some advantage to
them."

He gradually came to realise the vividness and variety of vegetable
life, and that a plant like an animal has capacities of behaving in
different ways under different circumstances, in a manner that may be
compared to the instinctive movements of animals. This point of view is
expressed in well-known passages in the "Power of Movement". ("The Power
of Movement in Plants", 1880, pages 571-3.) "It is impossible not to be
struck with the resemblance between the... movements of plants and many
of the actions performed unconsciously by the lower animals." And
again, "It is hardly an exaggeration to say that the tip of the
radicle... having the power of directing the movements of the adjoining
parts, acts like the brain of one of the lower animals; the brain being
seated within the anterior end of the body, receiving impressions from
the sense-organs, and directing the several movements."

The conception of a region of perception distinct from a region of
movement is perhaps the most fruitful outcome of his work on the
movements of plants. But many years before its publication, viz. in
1861, he had made out the wonderful fact that in the Orchid Catasetum
("Life and Letters", III. page 268.) the projecting organs or antennae
are sensitive to a touch, and transmit an influence "for more than one
inch INSTANTANEOUSLY," which leads to the explosion or violent ejection
of the pollinia. And as we have already seen a similar transmission of
a stimulus was discovered by him in Sundew in 1860, so that in 1862 he
could write to Hooker ("Life and Letters", III. page 321.): "I cannot
avoid the conclusion, that Drosera possesses matter at least in some
degree analogous in constitution and function to nervous matter." I
propose in what follows to give some account of the observations on
the transmission of stimuli given in the "Power of Movement". It is
impossible within the space at my command to give anything like a
complete account of the matter, and I must necessarily omit all mention
of much interesting work. One well-known experiment consisted in putting
opaque caps on the tips of seedling grasses (e.g. oat and canary-grass)
and then exposing them to light from one side. The difference, in the
amount of curvature towards the light, between the blinded and
unblinded specimens, was so great that it was concluded