Metempsychosis, in other words the doctrine of the transmigration of souls, teaches that the same soul inhabits in succession the bodies of different beings, both men and animals. It was a tenet common to many systems of philosophic thought and religious belief widely separated from each other both geographically and historically. Although in modern times it is associated among civilized races almost exclusively with the countries of Asia and particularly with India, there is evidence that at one period or another it has flourished in almost every part of the world; and it still prevails in various forms among savage nations scattered over the globe. This universality seems to mark it as one of those spontaneous or instinctive beliefs by which man’s nature responds to the deep and urgent problems of existence; whilst the numerous and richly varied forms which it assumes in different systems, and the many-coloured mythology in which it has clothed itself, show it to be capable of powerfully appealing to the imagination, and of adapting itself with great versatility to widely different types of mind. The explanation of this success seems to lie partly in its being an expression of the fundamental belief in immortality, partly in its comprehensiveness, binding together, as for the most part it seems to do, all individual existences in one single, unbroken scheme; partly also in the unrestrained liberty which it leaves to the mythologizing fancy.