As childhood, youth, maturity and old age pass, complex experiences come to the soul thus functioning here. Other souls functioning through physical bodies are encountered and various relationships are established. Out of the complexity of social, business, religious and political activities the soul gets a large and varied experience. Sooner or later the death of the physical body closes the chapter. The gathering of such experience has ceased, not because the soul has acquired all possible physical world knowledge, but because its instrument of consciousness here has worn out. Death cuts the soul off from its physical plane connection and the center of its consciousness is then shifted to the astral plane. There the purgative process goes forward, as explained in a previous chapter. As that proceeds the soul gradually gets free from one grade of astral matter after another and with the loss of each the man becomes conscious on a higher level. The physical body is lost suddenly but the matter of the astral body gradually wears away until there is so little left that the soul has lost connection with the astral world also. This means that the center of consciousness has shifted to the mental plane, or heaven world, where the man will function on the lower levels. There in the mental world, functioning through the vehicle of mental matter, a very important process goes on. The heaven world life is a harvest time in which assimilation of experience takes place. The consciousness there deeply broods over the experiences of life and extracts the essence from them which is transmuted into faculty and power for future greater expression. It is thus that the soul grows in wisdom and power through its long evolution. When the heaven life is finished, when the harvest of experience has been threshed out and the net gain has been built into the enduring causal body, the mental body, like the astral, has been completely dissipated. The end of a cycle of experience--of a day in the evolutionary school--has come and the physical, astral and mental bodies have all perished. Nothing remains but the soul, the real man, the ego, functioning through the causal body which persists. From that the ego again sends the forces outward, in the first activity toward rebirth, first forming a new mental body by drawing about itself the matter of the lower levels of the mental plane, then securing a new astral body on the astral plane and finally taking possession of another infant body in process of formation on the physical plane, into which it will in due course be reborn.