Consciousness in Plants. 329 
sensitiveness, and the transmission of a stimulus from the 
exciting point to another, which consequently moves. Yet 
plants do not, of course, possess nerves or a central nervous 
system. May we not therefore infer, and wisely so, too, 
that with animals such structures but serve for the more 
perfect transmission of impressions, and for the more com- 
plete intercommunication of their several parts? 
No structure in plants seems more wonderful, as far as its 
functions are concerned, than the tip of the radicle. Lightly 
pressed or burnt or cut, it transmits an influence to the upper 
adjoining part, causing it to bend away from the affected 
side. But more surprising, however, is the fact that the tip 
can distinguish between a slightly harder and softer object, 
by which it is simultaneously pressed on opposite sides. 
Let the radicle be pressed by a similar object a little above 
the tip, and it will be noticed that the pressed part does not 
transmit any influence to the more distant parts, but bends 
abruptly towards the object. Perceiving the air to be moister 
on one side than the other, it likewise sends out an influence 
to the upper adjoining part, which deflects towards the source 
of the moisture. When excited by light, the neighboring part 
bends from the light; but when excited by gravitation, the 
same part bends towards the centre of gravity. In almost 
every instance the ultimate purpose or advantage of the several 
movements can be clearly perceived. Two, or perhaps more, 
of the exciting causes often act simultaneously on the tip, and 
one conquers the other, doubtless in accordance with its im- 
portance for the life of the plant. The course pursued by the 
radicle in penetrating the ground being determined by the 
tip, has acquired for it the diverse kinds of sensitiveness which 
it possesses; and it is hardly an exaggeration to assert that 
the tip of the radicle thus endowed, and having the power to 
direct the movements of the adjoining parts, acts like the 
brain of one of the lower animals, which organ, seated within 
the anterior end of the body, receives impressions from the 
sense-organs, and directs their several movements. 
