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.
At the bottom of the sea there is a very curious zoophyte, the actinium, or sea-anemone. For a long time this creature was confounded with the plants, and held to be an ocean flower. Those who admire the beautiful, bright-coloured actinia, in the Garden of Acclimatization, in Paris, who look at them, waving on their flexible stem, shaking the coloured appendages and fringes which adorn their heads, find it hard to regard these charming queens of the waters otherwise than as real flowers. And, in fact, for ages, the sea-anemones were held to be marine plants.
In the last century, coral was held to be a marine shrub, and it was even believed that the flowers of the coral had been discovered. An academician of Paris, Count de Marsigli, created a European reputation for himself by this supposed discovery. Peyssonnel, a Provençal naturalist, found the utmost difficulty in opposing this idea, and in establishing the fact that these supposed flowers of the coral were in reality young corals. He had the whole Academy of Sciences against him; and his opposition to the ideas of the Academy brought him into such disgrace, that he was obliged to leave France and to go to the Antilles, where he died in obscurity as a doctor of medicine. And all this because he maintained that coral is not a plant, and does not produce flowers!
The famous Genevese naturalist, Charles Bonnet, anticipating the knowledge of our day by more than a century, has given a most interesting form to the parallel between animals and plants, in his work entitled Contemplation de la Nature. We cannot resist the pleasure of quoting the following passage, in which Charles Bonnet shows in a striking manner what are the difficulties in the way of distinguishing the plant from the animal, and how those difficulties are disposed of by those who dispute the sensibility of plants:—
"Everything is graduated in nature," says Charles Bonnet, "and, in refusing to admit that plants are sentient, we force nature to make a jump without any assignable reason.
"We observe that feeling decreases by degrees from man to the nettle, and to the mussel, and we persuade ourselves that it stops there, because we regard these animals as the least perfect. But there are, perhaps, many degrees between the feeling of the mole and of the plant. There are, perhaps, still more between the most and the least sensible of the plants. The gradations, which we observe, ought to persuade us to this philosophy; the new beauty which it adds to the system of the world, and the pleasure to be derived from the multiplication of sentient creatures ought to contribute to induce us to admit it. I willingly admit that this philosophy is much to my taste. I love to think that those flowers which adorn our fields and our gardens with a brightness constantly renewed, those fruit trees which are so pleasant to our eyes and our palate; those majestic trees that compose the vast forests, which time seems to have respected, are so many sentient creatures partaking after their fashion in the sweetness of existence.
"Plants offer some facts to our observation which seem to indicate that they possess feeling, but we are not likely to perceive those facts, because of the strong persuasion that they are insensible, which has prevailed among us for so long. We ought to agree to consider the question tabula rasa, and to subject plants to a new, impartial, and unprejudiced examination. An inhabitant of the moon, possessed of intellectual faculties like ours, but without any preconceived ideas about the insensibility of plants, would be the philosopher whom we require. Let us imagine such an observer engaged in studying the productions of our earth, and, after having given his attention to the polypes and other insects multiplied by the process of grafting, passing on to the contemplation of vegetables. He would, doubtless, take them at the period of their birth. With this view, he would sow seed of various species, and he would carefully watch their germination. Let us suppose that some of those seeds have been reversed in the sowing, the sprouting part turned downwards, the stem upwards; and the observer has the skill to distinguish one end of the seed from the other, and knows their functions. After some days, he will remark that the seed has grown into this reversed position, that the stem is turned upward, and the sprouting portion downward. He will feel no surprise; he will attribute a circumstance which is so hurtful to the life of the plant, to the mistake he has made in sowing the seed. But, continuing to observe, he will see the sprout and the stem each bending itself in the opposite direction, and trying to attain the right position. This change of direction will strike him as very remarkable, and he will begin to suspect that the organized being which he is studying is endowed with a certain amount of discernment. Too prudent, however, to pronounce upon these early indications, he will suspend his judgment and pursue his investigations. The plants whose germination our physicist has been observing, have been raised in the neighbourhood of a hedge. Thus favoured, and carefully cultivated, they have made great progress in a very short time. The soil which surrounds them at some distance is of two opposite qualities. That on the right of the plants is rich, damp, and spongy; that on the left is dry, hard, and gravelly. Our observer remarks that the roots, after having begun by extending equally on both sides, have changed their direction, and have spread out towards the rich and humid soil; over which they are stretching, and thus threatening to deprive the plants already there of their due share of nourishment. To prevent this inconvenience, he digs a ditch between the plants which he is observing and those they threaten to starve, and now he thinks he has provided against everything. But the plants, which he believes he has governed, disconcert all his precautions by extending their roots downwards, under the ditch, and gaining the other side.
"Surprised at this, he uncovers one of these roots, but without exposing it to heat, and holds a sponge steeped in water towards it. The root turns itself to the sponge, and when he changes its position, the root accommodates itself to each alteration.
"While our philosopher is meditating profoundly upon these facts, other facts equally remarkable present themselves almost simultaneously. He observes that all these plants have leaned away from the hedge, and are bending forward as though to present every portion of their bodies to the beneficent smiles of the sun. He sees that all the leaves are so turned that their upper surface is exposed to the sun, or to the fresh air, and that the lower surface is directed towards the hedge, or the ground. Former experience will have taught him that the upper surface of leaves serves chiefly as a defence for the lower surface, and that the latter is principally destined to pump up the moisture rising from the earth, and provide for the evacuation of what is superfluous. The direction of the leaves which he notices appears quite in harmony with his experiences. He studies this portion of the plant with increased attention.
"He remarks that the leaves of some species seem to follow the movements of the sun, so that in the morning they turn to the east, in the evening to the west. He sees that some leaves close themselves against the sun, others against the dew. He observes an analogous movement in certain flowers. Afterwards, he observes that no matter what the direction of the plants relative to the horizon has been, the direction of the leaves is always that which he has at first noticed, he bethinks him of changing this direction, and of placing the leaves in a position exactly contrary to their natural one. He has already had recourse to similar means in order to assure himself of the instinct of animals, and to ascertain its bearings. With this view he bends perpendicular plants towards the horizon, and keeps them in that position. Thus, the direction of the leaves is absolutely changed; the upper surface, which previously turned to the sun or to the fresh air, now looks towards the earth or the interior of the plant, and the lower surface, which formerly looked towards the earth or the interior of the plant, now turns to the sun, or the fresh air. But very soon all these leaves begin to move, they turn on their stem as on a pivot, and in an hour they will have resumed their former position. Our observer, wishing to assure himself whether leaves and branches when detached and plunged into water will preserve the inclinations which they manifest when upon the plant of which they formed a portion, subjects them to an experiment whose results leave him no doubt of the fact.
"He places wet sponges under the leaves, and he sees the leaves turn towards the sponges and endeavour to adhere to them by their lower surfaces. He also observes that certain plants, which he has shut up in his cabinet and in a cellar, have turned towards the window, or the grating respectively.
"Finally, the phenomena of the Sensitive Plant, its varied movements, the promptitude with which it contracts when touched, form the interesting subject which terminates his researches.
"Thus plentifully supplied with facts which all seem to tend to the support of belief in the sensibility of plants, which side will our philosopher take? Will he surrender to these proofs? Will he suspend his judgment? I think he will take the first part."[16]
Charles Bonnet believes, in short, that the plant, as well as the animal, is endowed with sensibility.
According to the system which we have developed, the animal is possessed of a soul, which is still very imperfect, and endowed only with faculties corresponding to its needs. But, since the animal, in addition to the sensibility enjoyed by the plant, possesses intelligence also, we must conclude from thence that the plant has not a soul, properly so called, but only the rudiment, the commencement, in other words, the germ of a soul.
We know that the sun has the privilege of giving birth to organic life upon our globe, his rays have power to produce the formation of living tissues, plants or zoophytes, when they fall upon the earth or the waters, and we may draw this conclusion from all that has gone before, that the sun sends down upon the earth animated germs under the form of his rays, which emanate from the spiritualized creatures who dwell in the king-star.
Thus our system of nature completes itself; thus, thanks to solar radiation, the two ends of the immense chain of organized beings whose place and part in the vast theatre of the worlds we have attempted to define are united. Life begins in the waters, its first appearance is in plants and zoophytes; for these two classes of living creatures obey the same laws, and appear to have the same origin. The sun, by sending his vivifying rays upon the earth, produces the formation of plants and zoophytes, which are the points of departure of organization. The animated germ deposited by the sun in plants and zoophytes grows, passes from the zoophyte to the mollusc, or articulated animal, and then undergoes a further development, by passing from the mollusc or articulated animal to the fish. This germ of a soul thus becomes a rudimentary soul, provided with certain faculties. In the zoophyte and the mollusc it had only sensibility; in the fish, and then in the reptile, and the bird, it has attention and judgment. The faculties are augmented in proportion as the animal mounts higher in the organic scale. Arrived at its summit, the human being, the soul is in possession of all its faculties, and especially of memory, which during the animal stages of the ascent is obscure and uncertain.
To accord sensibility to plants permits us to unite all the creatures of the living creation, and thus to complete our general system of terrestrial nature.