Leibnitz consistently applied this theory of scatulation to the human soul; he denied that either soul or body had a real development (_epigenesis_), and said in his _Theodicy_: "Thus I consider that the souls which are destined one day to become human exist in the seed, like those of other species; that they have existed in our ancestors as far back as Adam--that is, since the beginning of the world--in the forms of organized bodies." Similar notions prevailed in biology and philosophy until the third decade of the present century, when the reform of embryology by Baer gave them their death blow. In the province of psychology, however, they still find many adherents; they form one group of the many curious mystical ideas which give us a living illustration of the ontogeny of the soul. The more accurate knowledge which we have recently obtained, through comparative ethnology, of the various forms of myths of ancient and modern uncivilized races, is also of great interest in psychogeny. Still, it would take us too far from our purpose if we were to enter into it with any fulness here; we must refer the reader to Adalbert Svoboda's excellent work on _Forms of Faith_ (1897). In respect of their scientific and poetical contents, we may arrange all pertinent _psychogenetic myths_ in the following five groups: I. The myth of transmigration.--The soul lived formerly in the body of another animal, and passed from this into a human body. The Egyptian priests, for instance, taught that the human soul wandered through all the species of animals after the death of the body, returning to a human frame after three thousand years of transmigration. II. The myth of the in-planting of the soul.--The soul existed independently in another place--a psychogenetic store, as it were (in a kind of embryonic slumber or latent life); it was taken out by a bird (sometimes represented as an eagle, generally as a white stork), and implanted in the human body. III. The myth of the creation of the soul.--God creates the souls, and keeps them stored--sometimes in a pond (living in the form of _plankton_), according to other myths in a tree (where they are conceived as the fruit of a phanerogam); the Creator takes them from the pond or tree, and inserts them in the human germ during the act of conception. IV. The myth of the scatulation of the soul (the theory of Leibnitz which we have given above). V. The myth of the division of the soul (the theory of Rudolph Wagner [1855] and of other physiologists).--In the act of procreation a portion is detached from both the (immaterial) souls of the parents; the maternal contribution passes in the ovum, the paternal in the spermatozoa; when these two germinal cells coalesce, the two psychic fragments that accompany them also combine to form a new (immaterial) soul.