The subject treated in the following pages has made great progress in the course of forty years. Now what we are concerned with in psychical studies is always unknown forces, and these forces must belong to the natural order, for nature embraces the entire universe, and everything is therefore under the sway of her sceptre.

I do not conceal from myself, however, that the present work will excite discussion and bring forth legimate objections, and will only satisfy independent and unbiased investigators. But nothing is rarer upon our planet than an independent and absolutely untrammelled mind, nor is anything rarer than a true scientific spirit of inquiry, freed from all personal interest. Most readers will say: "What is there in these studies, anyway? The lifting of tables, the moving of various pieces of furniture, the displacement of easy-chairs, the rising and falling of pianos, the blowing about of curtains, mysterious rappings, responses to mental questions, dictations of sentences in reverse order, apparitions of hands, of heads, or of spectral figures,—these are only common place trivialities or cheap hoaxes, unworthy to occupy the attention of a scientist or scholar. And what would it all prove even if it were true? That kind of thing does not interest us."

Well, there are people upon whose heads the sky might tumble without causing them any unusual emotion.

But I reply: What! is it nothing to know, to prove, to see with one's own eyes, that there are unknown forces around us? Is it nothing to study our own proper nature and our own faculties? Are not the mysterious problems of our being such as are worthy to be inscribed on the program of our investigation, and of having devoted to them laborious nights and days? Of course, the independent seeker gets no thanks from anybody for his toil. But what of that? We work for the pleasure of working, of fathoming the secrets of nature, and of instructing ourselves. When, in studying the double stars at the Paris Observatory and cataloguing these celestial twins, I established for the first time a natural classification of those distant orbs; when I discovered stellar systems, composed of several stars, swept onward through immensity by one common impulse; when I studied the planet Mars and compared all the observations made during two hundred years in order to obtain at once an analysis and a synthesis of this next-door neighbor of ours among the planets; when, in examining the effect of solar radiations I created the new branch of physics to which has been given the name "radioculture" and caused variations of the most radical and sweeping nature in the dimensions, the forms, and the colors of certain plants; when I discovered that a grasshopper, eviscerated and kept in straw did not die, and that these insects can live for a fortnight after having had their heads cut off; when I planted in a conservatory of the Museum of Natural History, in Paris, one of the ordinary oaks of our woods (quercus robur), thinking that, if withdrawn from the changes of seasons, it would always have green leaves (a thing which everybody can prove),—when I was doing these things I was working for my own personal pleasure; but that is no reason why these studies have not been useful in the developing work of science, and no reason for their not being admitted within the scope of the practical work of specialists.

It is the same with these psychical studies of ours; only there is a little more passion and prejudice connected with them. On the one hand, the sceptics cleave fast to their denials, convinced that they know all the forces of nature, that all mediums are humbugs, and all experimenters imbeciles. On the other hand, there are the credulous Spiritualists, who imagine they always have spirits at their beck and call in a centre-table, who evoke, with the utmost sang-froid, the spirits of Plato, Zoroaster, Jesus Christ, St. Augustine, Charlemagne, Shakespeare, Newton, or Napoleon, and who set about stoning me for the tenth or twentieth time, affirming that I am sold to the Institute on account of a deep-seated and obstinate ambition, and that I dare not declare myself in favor of the identity of the spirits for fear of annoying my illustrious friends. The individuals of this class refuse to be satisfied just as much as the first class.

So much the worse for them! I insist on only saying what I know; but I do say this.

And if what I know is displeasing, so much the worse for the prejudices, the general ignorance, and the good breeding of these distinguished gentry, in whose eyes the maximum of happiness consists in an increase of their fortune, the pursuit of lucrative places, sensual pleasures, automobile-racing, a box at the OpÉra, or five-o'clock teas at a fashionable restaurant, and whose lives are frittered away along paths that never cross those of the rapt idealist, and who never know the pure satisfaction of his mind and heart, or the pleasures of thought and feeling.

As for me, a humble student of the prodigious problem of the universe, I am only a seeker. What are we? We have scarcely shed a ray more of light on this point than at the time when Socrates laid down, as a principle, the maxim, Know thyself,—notwithstanding we have measured the distances of the stars, analyzed the sun, and weighed the worlds of space. Does it stand to reason that the knowledge of ourselves should interest us less than that of the macrocosm, the external world? It is not credible. Let us therefore study on, convinced that all sincere research will further the progress of humanity.

Juvisy Observatory, December, 1906.

CONTENTS

LIST OF ILLUSTRATIONS