SPONTANEOUS MOVEMENTS IN PLANTS. 379 
generally to the distance of four or six feet, and in one instance 
as much as twelve feet. 
Many of the instances of spontaneous motion or irritability 
we have now recorded may doubtless be explained by the appli- 
cation of known physical laws. With others this is not so easy ; 
and it is but reasoning in a circle to say that because the 
organisms which manifest them belong to the vegetable kingdom, 
therefore the phenomena cannot be the result of a sentient 
force acting upon, and independent of, matter. Darwin has 
described how certain movements of the tendrils of climbing 
plants would be termed instinctive if they were observed in 
animals. The rapid rotatory motion of the zoospores of the 
lower Algae is absolutely undistinguishable from that of certain 
undoubted lowly organised forms of animal life. It is very 
difficult to distinguish between the movement of a shoot of a 
climber performing its circles in the air in search of a support, 
and that of the tentacula of a coral-polyp in search of food. 
The mode in which the Venus’s Fly-trap seizes and encages its 
prey is very like that adopted by a sea-anemone. Every fresh 
addition to our knowledge seems to confirm us in the view that 
it is unwise to dogmatise by laying down too rigid generalities, 
and absolutely to deny certain functions to whole classes of 
animated beings because we do not find them exhibited in the 
forms most familiar to us. I do not wish distinctly to claim 
for plants the actual possession of a voluntary or sentient 
faculty. But I do wish to point out that facts do not support 
us in asserting that a clear line of demarcation separates the 
animal from the vegetable kingdom ; the power of voluntary 
motion belonging to the one and not to the other. Taking all 
the facts we have described into consideration, the statement 
seems justified which has been made by one of our most expe- 
rienced naturalists, Professor Wyville Thomson* : — “ There are 
certain phenomena, even among the higher plants, which it is 
very difficult to explain without admitting some low form of a 
general harmonising and regulating function, comparable to 
such an obscure manifestation of reflex nervous action as we 
have in sponges and in other animals in which a distinct 
nervous system is absent.”! 
* Introductory Lecture to the Natural History Class at the University of 
Edinburgh, May, 1871. See “ Nature,” vol. iv. p. 91. 
t Since writing the above, I have met with the following remarks by 
the Italian botanist, Prof. Delpino (“American Naturalist,” July, 1871, 
p. 297) : — “ I must here, as always, declare myself a teleologist and a vitalist. 
Now teleology and vitalism, far from being vanquished by the Darwinian 
doctrine, find in it their most solid support. What do teleology and vitalism 
mean!? They mean that we believe that there is in all living things an 
