Is it not very natural that all the metamorphoses with which the world is covered should have made people imagine in the Orient, where everything has been imagined, that our souls passed from one body to another? An almost imperceptible speck becomes a worm, this worm becomes a butterfly; an acorn transforms itself into an oak; an egg into a bird; water becomes cloud and thunder; wood is changed into fire and ash; everything in nature appears, in fine, metamorphosed. Soon people attributed to souls, which were regarded as light figures, what they saw in more gross bodies. The idea of metempsychosis is perhaps the most ancient dogma of the known universe, and it still reigns in a large part of India and China.