From all the considerations, all the facts which we have just advanced, we conclude that the sensibility of plants is not to be contested, since no one can think of denying that privilege to certain zoophytes which can with difficulty be distinguished from vegetables.
We see an imposing tree, a stately oak with sturdy branches, growing on the sea coast. Not far off, on the sand of the shore, lies a star-fish flung there by the waves. A few yards below, on the surface of the water, floats a sponge, a branch of coral, a madrepore. When the icy wind blows, when the hurricane lifts the angry waves, which is it, the animal or the plant that will manifest sensibility to the tempest? The sponge, the coral, the madrepore will remain as indifferent to the fury of the elements as the rock in which they are incrusted, or as the pebble on which the star-fish stretches out its four motionless arms. But, the majestic oak will shudder at every gust of the tempest; he will bend his branches and shut up his leaves to shelter himself from the icy blast or the furious storm; and a mere glance at his attitude will indicate to you that an abnormal perturbation reigns in the atmosphere. Would you seriously say, in that case, that the vegetable feels nothing, and that the animal is sensible? Would you not, on the contrary, be inclined to declare that the tree is the sentient being, and that the star-fish, the sponge, the madrepore, are the creatures which are destitute of feeling?
Pause beside still water and seek for the polype or fresh-water hydra which we have just mentioned. You will find it difficult to disentangle this zoophyte from the reeds and willows which surround it. You will find, at length, a kind of membranous tube, a few centimetres in length. Is that the polype you were looking for? Is it not rather the stubble of some reed or grass plant? This living twig, with nothing to distinguish it in appearance from a herbaceous plant, is constantly fixed in the same place, like an aquatic vegetable. It makes some faint movements, consisting simply of the opening and shutting of the orifice of the tube, which solely constitutes its being. Sometimes it lengthens, sometimes it contracts itself, by stretching out membranous arms, as fine as threads, by means of which it seizes and drags towards it the water insects which chance to pass near it. This is the one single characteristic of its animality. At this rate, an aërial plant, the _fly-catcher_, would be just as much an animal as our polype, since it catches the insects which venture to crawl upon its leaves.