A
considerable proportion--a vast proportion, indeed--of the Moon-men had not
attained that level, and consequently had to reappear in this Earth-chain
as humanity. Besides this, a great mass of the animal kingdom of the
Moon-chain was surging up to the level of the individualization, and some
of its members had already reached it, while many others had not. These
latter needed further animal incarnations upon the Earth-chain, and for the
moment may be put aside.

There were many classes even among the humanity, and the manner in which
these distributed themselves over the Earth-chain needs some explanation.
It is the general rule that those who have attained the highest possible in
any chain on any globe, in any root-race, are not born into the beginning
of the next chain, globe or race, respectively. The earlier stages are
always for the backward entities, and only when they have already passed
through a good deal of evolution and are beginning to approach the level of
those others who had done better, do the latter descend into incarnation
and join them once more. That is to say, almost the earlier half of any
period of evolution, whether it be a race, a globe or a chain, seems to be
devoted to bringing the backward people up to nearly the level of those who
have got on better; then these latter also (who, in the meantime, have been
resting in great enjoyment in the mental world) descend into incarnation
along with the others, and they press on together until the end of the
period.

Thus the first of the egos from the Moon who entered the Earth-chain were
by no means the most advanced. Indeed they may be described as the least
advanced of those who had succeeded in attaining humanity--the animal-men.
Coming as they did into a chain of new globes, freshly aggregated, they had
to establish the forms in all the different kingdoms of Nature. This needs
to be done at the beginning of the first round in a new chain, but never
after that; for though the life-wave is centred only upon one of the seven
globes of a chain at any given time, yet life has not entirely departed
from the other globes. At the present moment, for example, the life-wave of
our chain is centred on this Earth, but on the other two physical globes of
our chain, Mars and Mercury, life still exists. There is still a
population, human, animal and vegetable, and consequently when the
life-wave goes round again to either of those planets there will be no
ne