Psychical philosophy has in all ages been furnished with at least one “working hypothesis” of the kind required. Its scientific name is “metempsychosis,” which in more popular language is known as “transmigration.” It teaches that after death the spirit enters into some other human body which happens to be living and unprovided with a soul; and the doctrine is frequently extended to include the idea that the new habitat may even be the body of one of the lower animals. Many of the most famous thinkers of Greece and the Orient were associated with the belief in question. It is to be found in the Bible and other sacred writings, and forms a part of the religions of many races throughout the world. It cannot, therefore, be lightly disregarded as a mere fantasy unworthy of consideration by civilised people in the twentieth century. As a matter of fact, the theory of transmigration fits in with modern observations. It does away with the necessity of a perpetual supply of fresh souls from extra-mundane regions. It also is consistent with, and explains, the absence of any vast overwhelming spirit-population. Moreover, it is the logical concomitant of our common, everyday experience. We are familiar with the occurrence of what we call “births,” that is, the coming into existence of new human bodies. We know also that these new bodies become, in some way or other, the temporary abodes of souls--the tenancy being sometimes a matter of minutes only and sometimes enduring for rather more than one hundred years. We see for ourselves that the habitation suits the tenant and that the tenant suits the habitation. What, then, can be more natural and fitting than that, when the tenant, for some reason or another, has to quit his dwelling, he looks out for another abode of much the same kind? So far from this course of action being fantastic and improbable, it is pre-eminently likely. The play of mere imagination is to be found altogether with those mental speculators who talk of the supposed departure of discarnate spirits to supposed spheres of existence beyond the earth.