The length of his stay in that world depends upon the amount of passion and emotion which he has developed within himself in his physical life. If there is much of these, the astral body is strongly vitalized, and will persist for a long time; if there is but little, the astral body has less vitality, and he will soon be able to cast that vehicle aside in turn. When that is done he finds himself living in his mental body. The strength of that depends upon the nature of the thoughts to which he has habituated himself, and usually his stay at this level is a long one. At last it comes to an end, and he casts aside the mental body in turn, and is once more the ego in his own world. Owing to lack of development, he is as yet but partially conscious in that world; the vibrations of its matter are too rapid to make any impression upon him, just as the ultra-violet rays are too rapid to make any impression upon our eyes. After a rest there, he feels the desire to descend to a level where the undulations are perceptible to him, in order that he may feel himself to be fully alive; so he repeats the process of descent into denser matter, and assumes once more a mental, an astral and a physical body. As his previous bodies have all disintegrated, each in its tarn, these new vehicles are entirely distinct from them, and thus it happens that in his physical life he has no recollection whatever of other similar lives which have preceded it. When functioning in this physical world he remembers by means of his mental body; but since that is a new one, assumed only for this birth, it naturally cannot contain the memory of previous births in which it had no part. The man himself, the ego, does remember them all when in his own world, and occasionally some partial recollection of them or influence from them filters through into his lower vehicles. He does not usually, in his physical life, remember the experiences of earlier lives, but he does manifest in physical life the qualities which those experiences have developed in him. Each man is therefore exactly what he has made himself during those past lives; if he has in them developed good qualities in himself, he possesses the good qualities now; if he neglected to train himself, and consequently left himself weak and of evil disposition, he finds himself precisely in that condition now. The qualities, good or evil, with which he is born are those which he has made for himself.