the astral, and finally the physical--and the soul returns
once more to incarnation.

It will now be understood how it comes about that a soul of average
development--on entering a new cycle, with the memory of the last
cycle considerably obliterated by the loss of the physical, astral,
and mental bodies, sheathed in new bodies on these planes, bodies that
have nothing in common with the life of the past--is unable to impress
its dim memories on to the brain; but it will also be seen that, with
the progress of evolution, the soul acquires ever clearer
consciousness in the causal body, in which it finally preserves the
memory of the various life-cycles. Since, at this stage, it has become
capable of projecting its vibrations, voluntarily, through the lower
bodies, it is able to transmit this memory first to the mental body,
then to the astral, and lastly to the physical body; when this is
possible, man, in waking consciousness, remembers his former lives.

This transmission requires a purificatory process in the vehicles and
a special training of the will. The matter of all the bodies--that of
the brain in particular--must be refined, its constituent elements
must be subtler, and its atoms must be fully awakened to
activity[246]; whereupon the cerebral cell becomes capable of
responding to the thought of the Ego, _i.e._, of vibrating in harmony
with the higher matter.

The second condition of the brain's receptivity is that this organ be
brought into a state of complete rest. So long as the waking
consciousness is active, the brain vibrates powerfully, and if, at
this time, the soul sends the brain its thought, this latter can no
more make an impression on the existing cerebral activity than a faint
note could be heard amid the clash of an orchestra. Consequently, man,
by the training of his will, must have acquired the power to stop the
thinking activity in the waking state, and to "centre" his attention
on the causal body, the only vehicle in which he can know the facts of
his past incarnations; this done he is able, at will, to project on to
his brain the scenes of his former lives and to imprint them thereon
with greater distinctness, in proportion to his development and
training.

In order to avoid continued explanations, we will deal with another
side of the question, however incomprehensible it be to such as have
not studied theosophy.

A vehicle of consciousness is both a registering apparatus[247] and a