INDIVIDUALS of whatever kind, or however numerous, are of no estimation in the universe; it is species alone that are existences in Nature, for they are as ancient and permanent as herself. To have a clear and distinct idea of this subject we must not consider a species as a collection or succession of similar individuals, but as a whole, independently of number or time, always active, and always the same; a whole which was considered but as one in the works of the creation, and therefore constitutes only a unit in Nature. Of these units the human species is to be placed in the first rank; all the others, from the elephant to the mite, from the cedar to the hyssop, belong to the second and third orders. Notwithstanding that they are different in form, substance, and even life, yet each sustains its appointed destination, and subsists independently of others, while the whole, in a general view, represents animated Nature, who has hitherto supported, and will continue to support, herself in the same manner as she is seen at present. Her duration is not to be estimated by a day, a year, an age, nor any given period of time, for time itself relates only to individuals, to beings whose existence is limited. It is not so with respect to species, for their existence is constant; their permanence produces duration, and their differences give rise to number. It is in this light that we must consider species, and give to each an equal right to the indulgence and support of Nature; for so she has certainly considered them, by bestowing on each the means of existing as long as herself.
Let us now consider the species as having changed places with the individual. In our preceding observations we have seen the relation which Nature holds in respect to man; let us now then take a view in what light she would appear to a being who represented the whole human species. We perceive that in the spring the fields renew their verdure, the buds and flowers expand, the bees revive from their state of torpor, the swallows return to our climates, the nightingale chaunts her song of love, the lamb frisks, and the bull laws with desire, and all animated creatures are eager to unite and multiply their species; and we can then have no ideas but those of reproduction and the increase of life. But when the dark season of cold and frost approaches, these same beings become indifferent to and avoid each other; many of the feathered race desert our clime, and the inhabitants of the waters lose their freedom under the massy congelations of ice; various animals dig retreats for themselves in the ground, where they fall into a state of torpor; the earth becomes hard, the plants wither, and the trees, deprived of their foliage, are covered with frost and snow; every object excites the idea of languor and annihilation. These appearances, however, of renovation and destruction, images, as it were, of life and death, although they seem general, are only individual and particular. Man, as an individual, concludes in this manner, but the being whom we have supposed as a representative of the species, thinks and judges in a manner more exalted and general; in that constant succession of destruction and renovation, and in those various vicissitudes, he perceives only permanence and duration. The different seasons in one year appear to him the same as those of the preceding, the same as those of millions of ages. The animal which may be the thousandth in the order of generation is the same to him as the first. In a word, if man had no period to his existence, and if all the beings by which he is surrounded existed in the same manner as they do at present, the idea of time would vanish and the individual would in fact become the species.
Let us then consider Nature for a few moments under this new aspect. Man certainly comes into the world enveloped in darkness. His mind is equally naked with his body; he is born without knowledge and without defence, and brings nothing with him but passive qualities. He is compelled to receive the impressions of objects on his organs; even the light shines on his eyes long before he is able to recognize it. To Nature he is at first indebted for every thing, without making her any return. No sooner, however, do his senses acquire strength and activity, and he can compare his sensations, than he reflects upon the universe; he forms ideas, which he retains, extends, and combines. Man, after receiving instruction, is no longer a simple individual, for he then, in a great measure, represents the whole human species. He receives from his parents the knowledge which had been transmitted to them from their forefathers; and thus, by the divine arts of writing and printing, the present age, in some sort, becomes identified with those that are past. This accumulation of experience in one man, almost extends the limits of his being to infinity. He is born no more than a simple individual, like other animals, capable only of attending to present sensations; but he becomes afterwards nearly the being which we supposed to represent the whole species; he reads what has past, sees the present, and judges of the future; and in the torrent of time, which carries off and absorbs all the individuals of the universe, he perceives that the species are permanent, and Nature invariable. As the relations of objects are always the same, to him the order of time appears to be nothing; he considers the laws of renovation as only counterbalancing those of permanency. An uninterrupted succession of similar beings, is, in effect, only equivalent to the perpetual existence of one of them.
What purposes then are gained by this immense train of generations, this profusion of germs, many thousands of which are abortive for one that is brought into life? Does not this perpetual propagation of beings, which are alternately destroyed and renewed, uniformly exhibit the same scene, and occupy the same proportion in Nature? From what cause proceed all these changes of life and death, these laws of growth and decay, all these individual vicissitudes, and reiterated representations of the same identical thing? They certainly arise from the very essence of Nature, and depend on the first establishment of the universal machine; the whole of which is fixed and stable, but each of its parts being endowed with the power of motion, the general movements of the celestial bodies have produced the particular ones of this terrestrial globe. The penetrating forces by which these immense bodies are animated, and by which they act reciprocally upon each other at a distance, at the same time animate every particle of matter; and this strong propensity, which every part has towards each other, is the first bond of beings, the ground of consistence and permanency in Nature, and the support of harmony in the universe. From these great combinations the smaller relations are derived. The earth moving on its own axis having separated the portions of duration into day and night; all its animated inhabitants have their stated periods of light and darkness, of their times of waking and sleeping. The action of the senses, and the motions of the members which form a great part of the animal economy, are related to this first combination; for in a world where perpetual darkness reigned, would there be senses alive to the enjoyment of light.
As the inclination of the axis of the earth, in its annual course round the sun, produces considerable variations of heat and cold, which we call seasons, all its vegetables have also, either wholly or partially, their seasons of life and death. The fall of the leaves, and the decay of fruits, the withering of herbs and the destruction of insects, depend entirely on this second combination. In those climates where there is not this variation, by the inclination not being so material, the life of the vegetable is not suspended, and every insect completes the stated period of its existence. Where the four seasons, in fact, make but one, as under the line, the surface of the earth is constantly covered with flowers, the trees have a perpetual foliage, and Nature seems to enjoy a continual spring.
Both in animals and plants, their particular constitution is relatively to the general temperature of the earth, and which temperature depends upon its situation and distance from the sun. If they were removed to a greater distance, neither our animals, nor our plants, could live or vegetate; the water, sap, blood, and all their liquors, would lose their fluidity; if on the contrary they were more near they would vanish and dissipate in vapour. Ice and fire are the elements of death, and temperate heat the first support of life. The living particles so generally diffused through all organized bodies are related, not only by their activity but number, to the particles of light which strike and penetrate almost all matter with their heat; for in every place where the sun can heat the earth with its rays, the surface will be covered with verdure, and peopled with animals; even ice is no sooner dissolved into water than it swarms with inhabitants. Water, indeed, is apparently more fertile than the earth; from heat it receives motion and life. In one season the sea produces more animals than the earth sustains; but its production of vegetables is infinitely less. And because that the inhabitants of the ocean have not a sufficient and permanent supply of vegetables, they are compelled to feed upon each other; and it is to this necessity that their immense multiplication may be referred.