Many years ago I wrote that to live means nutrition and generation, and the deeper I cast the sounding-line into the dark abysses of life, the more I am convinced that this definition faithfully depicts the most striking characteristics of all creatures which, from bacteria to man, come to life, grow and die on the face of our planet. If, however, I wished still further to simplify my idea, reducing life to its simplest and most essential form, I would say without fear of betraying the truth, that to live means to generate.

Every living body is perishable, but before dying it has the power of reproducing the form that has made it capable of living; and that whirlwind which absorbs and rejects, which assimilates new atoms and repels old ones, and which so clearly represents the eternal picture of life in all its manifestations, is also the most faithful representation of every form of generation.

Nutrition is a real genesis, and in the great chemical laboratory of living beings we have at all times before our eyes the reproduction of histological elements of organs and individuals. We lose hair, epithelia, white corpuscles every day; and yet every day we generate hair, epithelia and leucocytes: this is an every-day generation in the body of man. A nail falls off, a new one takes its place: this is the reproduction of an organ. We generate children similar to ourselves: this is the reproduction of an entire organism, the true generation. But in one of our offspring we see re-repeated a mole which is on our nose: this is the reproduction of an organ within an organism. On the other hand, one race generates another race, one species another species; and here we see a broader genesis by which from the reproduction of a cell through another cell we gradually pass to the generating of an organ, of an individual, of a race, of a species.

The world of living beings is a gigantic tree and from its trunk shoot forth the branches of classes, orders, species. On the branches leaves grow, which are the individuals; but each one of these small individuals generates within itself many cells, true organisms within greater ones. The world of living beings is but a great laboratory of prolific, incessant generation. Cells generate cells; organs, organs; species, species. An intimate brotherhood makes us members of one great organism—the placenta of living beings; and among ourselves we exchange the same matter which each of us in turn contributes to the work of apparent destruction, called nutrition, and to that of reproduction, designated as generation. To feed themselves and to generate, living beings are continually exchanging with each other a part of their own matter which, passing from one organism to another, seems to acquire new energy and new life. On the one hand, seaweeds live on mushrooms, carnivorous animals devour herbivorous, herbivorous feed on herbs, and man, the highest branch of the tree of living beings, partakes of all. On the other hand, males and females in continuous succession interchange part of their matter, remoulding their primitive forms.

The most elementary form of life is not, however, the cell, since at a lower stage we find the protoplasm, the true primum vivens which, by scission, generates the individual; and, by nourishing itself, nobody can tell what mysterious genesis of atoms it induces within its own most simple organism. The protoplasm cannot live without a continual exchange of matter, so that the live molecules of yesterday are dead today; and those which are alive today will be dead tomorrow; therefore nutrition also, in the last analysis, is an intimate and very mysterious generation.

Evanescence of forms is one of the most essential characteristics of living beings, and we give the name of death to the falling of every leaf from the tree of life. Man, also, drops some of these leaves every day—hair, epithelia, cells, which often produce a secretive substance and fall with it. Before dying, a part of the preËxisting form remains to re-animate the dead form and follows in its turn the parabolical cycle through which the mother form has passed. This is the most general principle and includes all possible kinds of generation, from that of scission to the highest form of sexual genesis. One would say that the life of an individual is only a moment of the great life of the species, of the classes, of the kingdoms of living beings; it is a spark which shoots off intermittently, passing from one organism to another.

Powerful and irresistible is the tendency to generate; in a great many cases the individual sacrifices himself consciously, or is unwittingly sacrificed by the laws of nature, provided that before death he transmit life to others. "Let the individual perish, if this preserve the species!" Such is the eternal cry of nature, which men and infusoria, oaks and mushrooms alike must obey. If the individual is protected and possesses preservative instincts and defensive organs, the species has a hundred bulwarks, a thousand manners of safeguard, more means of protection than are needed. In fact, living beings generate so profusely that one species alone would pervade the earth if the various circles of expansion, falling in with each other, did not struggle among themselves, like the circles caused on the smooth surface of a lake by a handful of sand thrown upon it by a child. Apart from the manner in which life is transmitted, there is an amount of life which passes away, there is a certain amount of fecundity, and this may seem, at first glance, most whimsical, while it is governed by the laws of preservation.

To be born and to die—fecundity and mortality—are so closely connected with each other that we can consider them as different aspects of the same phenomenon, as the action and reaction of life. When reproduction increases beyond measure, the dangers for the individuals generated increase at the same time, and destruction mows down the excessive number of those which are born. Now it is food that is no longer proportionate to the new-born; then parasites and enemies of the over-expanded species, which, increasing in turn, reËstablish the equilibrium. The destructive forces and the protective balance mutually, as happens with many other forces, simpler and better known.

The Malthusian problem, however, is much more intricate. If all species were equally prolific and had a life of equal length, the problem would, in fact, be reduced to a question of space and food; but, on the contrary, the duration of life and the various degrees of fecundity serve in turn to reËstablish the equilibrium by other ways. If the reproduction of mice were as slow as that of man, they would all be destroyed before another generation could be born; and even if they could live fifteen or sixteen years, not one of them, perhaps, would ever attain that age, surviving all dangers. And on the other hand, should oxen multiply in the same proportion as infusoria, the entire species would die of hunger in a week.

In order that an organic form be preserved, the individual must preserve itself and generate other individuals. Now these forces must vary inversely. If the individual, through its simple organization, is little fit to resist danger, it must countervail this weakness with reaction, generating intensely. If, on the contrary, high qualities give it a great capacity for self-protection, it should then diminish its fecundity proportionately. If danger is reckoned as a constant quantity, inasmuch as capacity for resistance should be equal in all species, and does consist of two factors (faculty to maintain individual life and power to multiply it), these factors cannot but vary in opposite directions. This most simple and sublime law, which Herbert Spencer read in the great book of nature, is one of those that rule with the most inflexible tyranny the elementary phenomena of reproduction, as well as the highest and most complex phenomena of human love.

In the DiatomaceÆ the fecundity by scission is gigantic: Smith reckoned that a single gnat could create a thousand million individuals in one month. A young Gonium, capable of scission after twenty-four hours, can produce in a week 268,435,456 individuals equal to itself. In other cases, the process of multiplication is not scissiparous, but endogenous, as with the Volvox; but the reproduction is always extraordinary. If all the individuals generated should survive, a Paramecium would, by scission, produce in the course of a month 268,000,000 individuals. Another microscopic animal can produce 170,000,000,000 individuals in four days. The Gordius—the entozoÖn of an insect—lays 8,000,000 eggs in less than a day. An African termite lays 80,000 eggs in twenty-four hours, and Eschricht reckoned at 64,000,000 the number of eggs in the adult female of an Ascaris lumbricoides.

If, from the minute microscopic creatures exposed to every danger and which consume very little matter—if, from these living atoms of which you could gather as many in your hands as there are men on earth, you pass to the elephant, you have there a giant of flesh that requires thirty years of its life to become fecund, and then, after a long gestation, produces but one offspring. And above the elephant you find a giant of thought, Man, who requires the third part of his average life to reproduce himself, and after nine long months generates one child only; and, what is worse, he sees half of his offspring mowed down before they are able to bear flower and seed.

The methods of transmitting life are manifold, since nature in no other function has been so inexhaustibly rich with forms as in generation; but we, dealing here with the general physiology of love, will reduce all the various generative forms to these few:

Separation or Scission.—The individual dissevers into two parts, and each of these, made independent, reproduces the generator. This is the most simple form of genesis, in which the function of reproduction is not distinct from the other functions, but merges into them.

Endogenesis.—Within an individual many other individuals are formed; the parent opens, and, destroying its own individuality, dissolves in its offspring.

The individual by itself alone generates other individuals.—The parent generates through special organs and without dissolving in its offspring. The individuals generated and separated from the generator are eggs, seeds, perfect organisms; but in every case these are always elements evolved within the generator through special organs. The generative function is already marked and distinct in a laboratory which detaches and prepares some of the elements of the individual, so that they may reproduce it.

Monoecious Sexual Generation.—A step higher, the generative laboratory becomes complicated and divides into two parts, one of which brings forth the egg, the other the fecundating element. Each, for its own account, prepares the element destined for the reproduction of the individual; but if both do not come in contact, the new being is not generated. We have the sexes quite distinct, but enclosed within a single individual. Strange to observe, however, we behold an individual that generates an egg which cannot be fecundated by that individual's seed; or an individual that produces a seed which cannot be of any service to the egg. A duplex embrace of two hermaphrodites which interlace a quadruple love, and the appearance of winds, insects, or birds, as fecundatory paranymphs, resolves these problems of a most singular generation.

Dioecious Sexual Generation.—Finally, the generating organs, too, separate and fix themselves each upon a single individual, which is sterile in itself, produces but one of the generating elements, and, therefore, must combine with the other; and by such union they may produce the new creature: the sum of two individualities, the male and the female, the father and the mother. Man loves in twain; but although, like the other superior animals akin to him, he presents a dioecious sexual generation, yet in his inmost tissues he also possesses the endogenous genesis and the genesis by scission, and presents in this regard the remains also of the elementary forms of life enclosed within him.

In this rapid course through all the forms of generation we see delineated the same laws by which nature rules the other functions. Gradually new forces appear and new organs are brought forth to represent the subdivision of work. First, it is the whole individual that generates, then an organ of the individual, then again two organs in the same individual, and again two organs in separate individuals. In the many forms of genesis, the unity of the plan is more than ever manifest, and we, the highest of all living creatures, while, like the amoeba, we have in our protoplasm and scattered all through the mass of our body the faculty to generate, recognize in man and woman the two distinct laboratories which prepare the seed and the human egg.

While the pathology of love, in many cases of lasciviousness, shows the last declining remains of a promiscuous hermaphroditism, imagination, a forerunner of science, causes us to divine that in more complex creatures sexes may be more than two, and generation presents a deeper subdivision of work, in the same manner as in the cynical or skeptical distinctions between platonic and sensual loves and in the most daring polygamies of soul and senses we perceive in the distance other lights which disclose to us the horizon of new and monstrous generative possibilities, some of them reaching the suprasensible and some as base and brutal as the most repelling atavic regressions.

When the science of the future will permit our posterity to connect all the phenomena of nature, from the most elementary to the most complex, from the simplest motion of a molecule to the flash of the most sublime genius, in an uninterrupted chain of facts, then perhaps the first origins of love will be sought in the elementary physics of dissimilar atoms which endeavor to find each other and combine, and with opposite motion generate the equilibrium. The positive electric body seeks the negative, the acid seeks the base, and in these conjunctions, with great development of light, heat and electricity, new bodies are formed, new equilibriums obtained; it seems that Nature renews her forces and, rejuvenescing, prepares herself for new combinations and new loves.

And is not love perhaps the combination of two dissimilar atoms which seek each other and combine, notwithstanding all the adverse forces of heaven and earth? And in the same manner as the molecule of potassium snatches the oxygen away from water with a great development of light and heat, is not the union of those two molecules, which we call man and woman, accompanied by a hurricane of passion, by flashes of genius, by infinite glittering of flames and ardor? Do we not perceive a pandemonium of physical and psychical forces accumulating, battling and equilibrating around that point where a man and a woman are attracted toward each other, to rejuvenate the human matter and rekindle the torch of life?

A particular motion, originated in the ovary and in the testis, accumulates such energy in the nervous centers as eventually to bring the masculine element in contact with the feminine, so that the generative gemmulÆ produced in the slow laboratory of two different organisms reunite in that nest which is the maternal womb and where the fecundated egg must transform into a human being.

The poet and the metaphysician may define love in whatever manner they choose. There is only one definition for science: Love is the energy which must bring in contact the egg with the seed; without ovary and without testis there can be no love.

That forward movement which is called generation is so powerful as to oppose and even destroy the minor motion, that is, the preservation of the individual; and while each individual rotates, it is carried forward with a movement a hundred times more irresistible and powerful through space and time. The first motion represents the narrow life of the individual and is protected by egotism; the second is the great life of the species, and love defends it.

The most superficial study of the generative function is sufficient to convince us that love is always a phenomenon of high chemistry, in which the generating atoms, in order to combine, must be neither too similar nor too dissimilar. No sooner has sex manifested itself in animals than we have in the same individual, but in two distinct laboratories, the formation of two generative elements. Sex, which, at first thought, appears to us as one of the deepest mysteries of life, is nothing but a laboratory which attracts the elements generated by every element of the organism, and encloses and preserves them in itself in order to pour them into the bosom of other elements, similar but not equal, generated in another laboratory, that is, the opposite sex. When the two generative laboratories are separated in two distinct organisms, it is probable that the diversity of their gemmulÆ is greater. If in individuals closely resembling each other, but of different races, we combine the generative elements, we still will probably have fecundity; while, if we pass to different species, fecundity will be more difficult; if we pass to different genera it will in most cases become impossible.

But let us set aside the words species and genera, which, in nature, have not the same value as we assign to them in our museums and in our books, and let us, instead, take from the world of the living a handful of animals, haphazard, so that we may gather together brothers, cousins, nephews, individuals of the same or affinitive classes, genera, orders, and let us place them in line, in the order of their degrees of similarity. Should we try to couple them, or study their spontaneous loves, we would find cases of sterility in beings too similar and in beings too dissimilar; therefore, generation moves between these two opposite poles, too great similarity and too great dissimilarity. That is the reason why we may see a woman with a mustache, atrophied breasts and deep voice remain sterile with a robust man: they do not generate because they have too close a resemblance. That is the reason why a dog and a cat are sterile: they do not generate, because they are too dissimilar. Nature said to living beings: "If you wish to love, be neither too similar nor too dissimilar."

Let us try and discover the reason of this law. Germs that are too similar cannot concur in fecundation, or fecundate unsatisfactorily, perhaps through the same laws of elementary physics and chemistry which cause bodies to repel other bodies equally electrified or with which they have too close a resemblance in their physico-chemical characteristics. Try the combination of sulphur with phosphorus, of iodine with bromine, and, on the other hand, observe the ardent loves of chlorine and hydrogen, of potassium and oxygen. The fecundity of two different organisms is, besides, an energy bearing in one direction; it is the sum of resistances all of them equal, while two quantities, different but susceptible of being summed, give a greater number of diverse resistances and have, therefore, a greater possibility of living and resisting external enemies. An individual is the sum of many victories over exterior elements, the result of many and infinite adaptations to the ambient which surrounds it. Two individuals dissimilar, but not enough to impede generation, will bring together those adaptations and those victories through which the new creature enjoys the possibility of resistance and will meet with fewer dangers.

It is much easier to explain why forms too dissimilar cannot love each other. This impossibility is one of the most powerful means of preserving the living forms, extremely varied, in those conditions which are useful to their existence. When a living being has come out of the struggles of life, when it has yielded to external agents and enemies in a certain way, it transmits itself to future generations in that form and nature which are the fruit of a long and successful battle. Precisely for the same reason, an herbivorous animal, which is the offspring of another that has gained its flesh with herbs, cannot grow and multiply except by feeding on herbs. Imagine for a moment that organs and tissues feeding on meat should be grafted on to the organs and tissues of an herbivorous animal. What disorders would not arise! A fragment of carnivorous animal closed up in an organism which has teeth to chew herbs, gastric juice to digest herbs, intestinal tube to assimilate herbs, and olfactory nerves which find leaves and flowers delectable! The apparent stability of the species, which in fact resolves itself in a slow mutation, is nothing therefore but the unavoidable necessity for male and female to pour into the crucible of generation elements that can combine, metals that can fuse, forming a homogeneous and compact alloy.

From the elementary physics of generation you may jump to the most ardent sympathies, to the juxtaposition of human characters in the nest of love, and you will see that the same law rules all and each of these facts. Neither too similar nor too dissimilar. Love is the sum of analogous but not identical forces; it is the complement of complements; it is the square of squares; it tolerates neither subtractions nor divisions.

We shall see at every step of our studies the same laws which govern generation, or the so-called physical love, re-appear in the high spheres of love. For us, love is simply one function which, to be understood, must not be barbarously mutilated and disrupted so as to have one part of its limbs sent to the laboratory of physiology, and the other left in the library of the philosopher. Love is such energy that from the lowest grades of the most automatic instinct it ascends to the highest regions of the suprasensible, and perhaps no other psychical element reaches to more distant poles.

Think of the shepherd of the high Apennines who loves a goat, and of Heine, who in the clutches of death wants to be brought to the Louvre to see the Venus of Milo once more, and you will have a pallid idea of the frontiers which this ardent, tenacious, violent, multiform passion called love seeks to conquer.

While in the field of chemical facts generation marks the highest point of molecular chemistry, in the psychological field love reaches the loftiest summits of the ideal. Love is the force of forces; it makes its appearance when man is strongest; it vanishes when age has weakened him. Love is the joy of joys, it is at the bottom of every desire, of all riches, on every horizon of pleasure; it is always the highest aim. If we except men who were born without gentle feelings, in every human sky love is the brightest star; it is the sun of every firmament. It is the strongest, the most human, the richest of passions.

In all forms of generation, whether agamous or sexual, by scission or by endogenesis, whether we consider the son in comparison with the father, or with far Adam, we behold the generated preserve a part of the last or of the first generator, so that the motion communicated from the first to the last generation is transmitted without interruption. Take as the starting-point the Adam of the Bible or the Adam of progressive evolution, the clay breathed into by a God or the Darwinian ascidia: each one of us has still within himself a material part belonging to the first man or first father of all men, so that an immense brotherhood unites all living beings. To the divination of the poet who, beholding the flowery meadows, the forests, the swarming of animals, cries out with emotion: "O Mother Nature!" science answers in accord, as it contemplates a quantity of matter and a quantity of life pass from one to the other of those organisms called individuals. For every life extinguished a new life is born, and within us, who occupy the loftiest place among all the living beings on this planet, quiver and vibrate the molecules which have passed through thousands and thousands of existences and thousands and thousands of loves.

If love is the warmest and the most human of passions, it is also the richest. To its altar every faculty of the mind carries its tributes, every throb of the heart carries its fire. Every vice and every virtue, every shame and every heroism, every martyrdom and every lewdness, every flower and every fruit, every balm and every poison may be brought to the temple of love. Everything human can be carried away in the whirlwind of love; and more than once man regrets that he possesses but one life to offer as a holocaust to this god. And yet this gigantic force is the least governed of all the passions. It would seem that before it man feels too small and too weak; and just as the savage falls on his knees before the lightning and weeps, or flees, the civilized man, even today, is terrified before the unexplored hurricane of this sovereign force, and acknowledges his powerlessness and his ignorance. In the delirium of voluptuousness and in the storm of desperation, he lets himself be carried away by a force which he considers superior to reason, too powerful in comparison with his weakness. In his codes he writes, timidly, laws which he violates every day; opprobrious punishments which the juries always cancel; and a dense fog of ignorance surrounds the temple of love, which he enters nearly always as a thief and from which he emerges nearly always as an outcast. Our legislation on love is a wretched connubiality of hypocrisy and lechery, and as we know not how to look love in the face, we disguise it with the garments of the buffoon and the prostitute. Our laws are so perfect that many must not love, and very many cannot love; and while we all weep over the few victims of hunger, we shrug our shoulders at the hundreds of thousands who die in celibacy for not having been able to gather the straw for their nests, and we laugh at the millions of celibates who know nothing of love save masturbation and prostitution. In the presence of love we are still more or less savage—the basest brutishness before the most powerful of human forces!

Yet love also should be conquered like all other forces of nature; and without losing a fraction of its energy, or a flower of its garden, it also must be governed by science, which understands and directs all things. The lightning which prostrates the savage in the dust of fear is guided by us on the small wire of the conductor, gilds the ornaments of our women and transmits our thoughts from one hemisphere to the other. This other lightning, also, which, more powerful and more dangerous, explodes in the hurricanes of the human heart, must be studied, guided and reduced to a live force that can be measured, weighed and governed. Love should be the dearest, the most precious, the most powerful of civilized forces. No other passion can claim supremacy where it appears; no other can solve the sublime problem of combining the greatest voluptuousness with the greatest virtue, of generating the good of future beings through the joy of the living ones, of transmitting civilization to posterity in the spasm of an embrace.

LOVE IN PLANTS AND ANIMALS