Some men succeed in shaking themselves free of this etheric envelope in a few moments; others rest within it for hours, days or even weeks.
Nor is it certain that, when the man is free from this, he will at once become conscious of the astral world.

For there is in him a good deal of the lowest kind of astral matter, so that a shell of this may be made around him.

But he may be quite unable to use that matter.

If he has lived a reasonably decent life he is little in the habit of employing it or responding to its vibrations, and he cannot instantly acquire this habit.
For that reason, he may remain unconscious until that matter gradually wears away, and some matter which he _is_ in the habit of using comes on the surface.

Such an occlusion, however, is scarcely ever complete, for even in the most carefully made shell some particles of the finer matter occasionally find their way to the surface, and give him fleeting glimpses of his surroundings.
There are some men who cling so desperately to their physical vehicles that they will not relax their hold upon the etheric double, but strive with all their might to retain it.