than animal nerves. An assumption like this is not absolutely necessary. It is impossible to say that cer- 
tain vegetable organs and tissues only discharge one function ; it is perfectly conceivable that they may be 
endowed with two or more, abstractedly. Who, for example, could witness an oscillatorial filament wriggle 
itself out of a plate, and move towards the light with an invincible pertinacity, and could feel a doubt that it 
possessed the instinct that light was good for it ; in obedience to which impulse, it was using every effort in 
its power to reach it ? Place by its side a humble animalcule, which, with movements of equal vivacity, 
dances hither and thither in its native element, and let science put her finger upon the point where sensa- 
tion ceases on the one side, and some new faculty commences on the other. 
“ Here are plants folding close their delicate organs from the cold evening air, expanding them again to 
their genial sunbeam ; here are plants shrinking from the drenching rain, or opening to welcome the refresh- 
ing shower, as their different constitutions may suggest ; here are some casting forcibly off every intruder to 
the honey cell ; here are others, on the contrary, spreading their leafy traps for the capture of such offenders, 
here are a few abashed and shrinking from the touch ; and finally, were St. Vitus’s Dance a vegetable ma- 
lady too, here is one — the Desmodium gyrens — which is decidedly a victim to it. 
“ Leaving, however, the discussion to another and more befitting arena, we would proceed to indicate 
that, putting aside the question of the amount of sensation involved in the motions referred to, there are 
other and even more remarkable points of view from which to contemplate the subject. 
“ There is a class of poisons which may be shewn to operate purely upon the sensation of animals, 
causing no chemical or physical disorganisation of their structure ; these are opium, belladonna, Prussic acid, 
nux vomica, tobacco, &c. If now, it can be shewn that these agents act in a deleterious manner upon 
plants, we have the presumptive evidence of strong analogy in support of the idea of vegetable sensation. 
M. Marcet has set the question at rest. From his experience it has been found that, even in minute quan- 
tities, the poisons specified are destructive to vegetable life. If a leaf of the sensitive plant is cut off, and 
placed in pure water, it curls up its leaflets, but in a short time they again expand, and retain their irrita- 
bility for several days, expanding and shrinking up as on the plant itself, when untouched with the finger or 
with a needle ; but if another leaf is cut off, and placed upon water, to which a solution of belladonna has 
been added, the leaflets collapse, and subsequently expand ; but after this it seems paralysed — its life is ex- 
tinct, and even if it is then put into pure water, it no longer can be made to contract. Electricity, extreme 
cold, mineral poisons, arsenic, &c. are productive of similar consequences. Every one is familiar with that 
simple experimental, the fumigation of a rose-tree, to destroy the insects which infest it. It affords us an 
instance of the action of a narcotic poison not only upon the insects, but also upon the plant itself. The 
little creatures tumble from the branches, stupified with the tobacco fumes. And at the same time it may 
be observed that the leaves of the rose droop, some of its youngest and tenderest branches hanging down, 
and only recovering, after exposure to a purer atmosphere, their former position and healthy aspect. The 
effect of these poisons obviously indicates that all plants possess an occult principle, having a certain analogy 
to sensation. It is found, also, that when certain chemical substances in solution are presented to their 
roots, the foreign matter is carried into the circulating system of the plant, but is almost invariably, if it is 
unsuitable for its nutrition or for the formation of its secretions, carried down again, and thrown off by the 
roots. Even in the selection of its proper food by the delicate spongiole of the root, it would seem as if 
some kind of discerning faculty were in operation, which at any rate may be compared to animal instinct. 
The struggle which plants growing in a cellar or darkened room make towards the light, however small 
the glimmer which may pierce the darkness, and the sedulous manner in which the radicle and plumule of 
the germ respectively avoid and seek the same influence, seem to speak in similar language. Every one who 
has watched the growth of the tendril of the vine, or the stem of the creeping-plant, must have observed 
that neither make any turns until they come into contact with some object around which they can twine ; so 
that, up to a certain point, the stem of the most inveterately-twisting plant remains as straight as possible ; 
but at the point of contact with another body, a volution immediately commences, and thenceforward it 
proceeds in a spiral direction around the object held in its embrace. In the case of the briony, simple con- 
tact with the object is not sufficient to cause the twisting of the stem. To prove this, the experiment of 
tying it with a string at a certain point has been made ; but the plant made no attempt to twist at that 
point. A small weight was then attached to the string, and the tendril immediately began to shorten itself 
by making several spiral turns. This seems to indicate that the tendril of the briony, naturally, will twist 
only when it has the weight of the stem to support. The writer who records this experiment, and whose 
striking phraseology is almost indicative of his name, adds, £ it is a hand seeking in the dark, and grasping 
what it has felt by the action of muscles remote from the sensible point.’ 
“ The remarkable manner in which plants search for their food, within certain limits comparable to that 
of animals, appears to imply the existence of some higher impulse than mere fortuity. The strawberry 
plant will thrust its c runners ’ completely across a garden walk, on to a bed of soil on the opposite side, 
where it will for the first time, as it were, perceiving its object to be gained, push out roots, and form a new 
plant. It is not uncommon to find travellers relating the most singular freaks played by trees and plants in 
quest of nutriment. Trees are sometimes found which have taken root on one side of a deep ravine, and 
having exhausted the sterile soil on that side, have pushed forth roots completely across the abyss, which 
have gained its opposite side, and there struck deep into more fertile ground. Plants are often to be found 
which have rooted in old walls ; but soon experiencing the want of soil, extend long roots in the direction 
of the ground, which they penetrate, and then form radicles. If the roots of a plant are accidentally denuded, 
and there happens to be some moist substance, as wet moss, in their neighbourhood, they direct themselves 
towards it, and eventually succeed in reaching it.” 
