ced, and
it takes instinctive steps to defend itself and to maintain its position as
long as possible. The matter of the astral body is far more fluidic than
that of the physical, and this consciousness seizes upon its particles and
disposes them so as to resist encroachment. It puts the grossest and
densest upon the outside as a kind of shell, and arranges the others in
concentric layers, so that the body as a whole may become as resistant to
friction as its constitution permits, and may therefore retain its shape as
long as possible.

For the man this produces various unpleasant effects. The physiology of the
astral body is quite different from that of the physical; the latter
acquires its information from without by means of certain organs which are
specialized as the instruments of its senses, but the astral body has no
separated senses in our meaning of the word. That which for the astral body
corresponds to sight is the power of its molecules to respond to impacts
from without, which come to them by means of similar molecules. For
example, a man has within his astral body matter belonging to all the
subdivisions of the astral world, and it is because of that that he is
capable of "seeing" objects built of the matter of any of these
subdivisions.

Supposing an astral object to be made of the matter of the second and third
subdivisions mixed, a man living in the astral world could perceive that
object only if on the surface of his astral body there were particles
belonging to the second and third subdivisions of that world which were
capable of receiving and recording the vibrations which that object set up.
A man who from the arrangement of his body by the vague consciousness of
which we have spoken, had on the outside of that vehicle only the denser
matter of the lowest subdivision, could no more be conscious of the object
which we have mentioned than we are ourselves conscious in the physical
body of the gases which move about us in the atmosphere or of objects built
exclusively of etheric matter.

During physical life the matter of the man's astral body is in constant
motion, and its particles pass among one another much as do those of
boiling water. Consequently at any given moment it is practically certain
that particles of all varieties will be represented on the surface of his
astral body, and that therefore when he is using his astral body during
sleep he will be able to "see" by its means any astral obje