The Spirits' Book
Book Two - The Spirit World
Chapter I - Spirits
93. Is the spirit uncovered or is it enveloped in a substance of some kind, as postulated by some?
“The spirit is enveloped in a vaporous substance, as you perceive it, although that would seem too heavy and cumbersome to us. It is sufficiently vaporous to allow a spirit to float in the atmosphere and travel through space as it so desires.”
As the seed of a fruit is surrounded by the perisperm, the spirit is surrounded by an envelope that, by analogy, may be called the perispirit.