A human being dies every second on the whole terrestrial globe; that is, eighty-six thousand four hundred per day, about thirty-one millions per year, or more than three milliards per century. In ten centuries more than thirty milliards of corpses have been committed to the earth and given back to general circulation under the form of various products,--water, gas, etc. If we keep an account of the diminution of human population as we count up the historic ages, we find that for ten thousand years, _at least two hundred milliards of human bodies have been formed from the earth and from the atmosphere by respiration and nourishment, and have returned to it_. Molecules of oxygen, hydrogen, carbonic acid, and nitrogen, which have constituted these bodies, have enriched the earth and been given back to atmospheric circulation. Yes, the Earth we inhabit is now formed partly of the milliards of brains which have thought, the milliards of organisms who have lived. We walk over the remains of our ancestors as our descendants will walk over ours. The brows of thinkers; eyes which have looked, smiled, and wept; mouths which have sung of love, rosy lips, and marble bosoms; mothers' flesh and blood; the arms of toilers; the muscles of men, good and bad,--all who have lived, all who have thought, lie in the same earth. It would be difficult now to take a single step on the planet without walking on the remains of the dead; it would be difficult to breathe without inhaling the breath of the dead. The constructive elements of the body draw upon Nature and are returned to Nature, and each one of us bears in himself atoms which have formerly belonged to other bodies. Ah, well! Do you think that can be all of humanity? Do you think it may not have left something nobler, grander, and more spiritual? Does each of us give the universe, when we breathe our last, nothing but sixty or eighty kilos of flesh and bone which will disintegrate and return to the elements? Does not the soul which animates us endure by the same right as each molecule of oxygen or nitrogen or iron? And all the souls that have lived, do they not still exist? We have no right to affirm that man is composed solely of material elements, and that the thinking faculty is only one property of the organization. On the contrary, we have the strongest reasons for admitting that the soul is an individual entity, that it is that which governs the molecules to organize the living form of the human body. What becomes of the invisible and intangible molecules which have composed our body during life? They will belong to new bodies. What becomes of the equally invisible and intangible souls? It may be thought that they also reincarnate themselves in new organisms, each in accordance with its nature, its faculties, and its destiny.