Personally, I declare that I have not yet discovered for myself one fact which proves with certainty the existence of soul as separate from body. Otherwise, however sublime astronomical science may be,--though it stand at the head of human researches, as the first, the most important, and the most widespread of all sciences,--I avow that, if the inductive method had permitted me to penetrate secrets of existence, I should inevitably have abandoned the science of the firmament, for that which would have dethroned the other through its prime and unequalled importance; since it would be superfluous for us to evade the fact that the gravest and most interesting of all questions, to ourselves, is that of our continuous personal existence. The existence of God, of the entire universe, touches us far less intimately. If we ever cease to live (for what is the span of a human life in the light of eternity!) it is a matter of utter indifference to us whether other things exist or not. Doubtless this reasoning is severely egotistic! Ah, how can it be otherwise? If we have no clear and irrefutable proofs, we have still the aid of a goodly number of observations, establishing the conclusion that we are compassed about by a set of phenomena, and by powers differing from the physical order commonly observed day by day; and these phenomena urge us to pursue every line of investigation, having for its end a psychical acquaintance with human nature. Let us begin at the beginning, with a recital of observations which, from their very nature, have the disadvantage of being very personal. 2 At the age of sixteen, on my way home one day from the Paris Observatory, I noticed, on the bookseller's stand in the Galeries de l'Odeon, a green-covered volume entitled Le Livre des Esprits (Book of Spirits), by Allan-Kardec. I bought it, and read it through at a sitting. There was in it something unexpected, original, curious. Were they true, the phenomena therein recounted? Did they solve the great problem of futurity, as the author contended? In my anxiety to ascertain this I made the acquaintance of the high-priest, for Allan-Kardec had made of Spiritism a veritable religion. I assisted at the seances. I experimented and became myself a medium. In one of Allan-Kardec's works, called Genesis, over the signature of Galilee, may be read a whole chapter on Cosmogony, which I wrote in a mediumistic condition. I was at that time connected with the principal circles in Paris where these experiments were tried, and for two years I even filled the exacting position of secretary to one of these circles, an office which morally bound me not to be absent from a single seance.