Note:
To avoid confusion for those who have read elsewhere in these 21 Outlines of the Brotherhood of Light Study Books, when referring to the faster-than-light velocity, slow-time properties of the astral plane, the terms "astral', "stellar", "'four-dimensional" and "inner" all refer to astral properties .To avoid confusion throughout these brief notes, only the two terms "astraL" and "stellar" will be used to refer to high-velocity, slow-time astral energies.

Physical- cells Compose the Physical Body.
Thought- cells Compose the Astral Body.

Just as protoplasm, the chief substance of the physical body, is organized into living cells, so psychoplasm, the chief substance of the astral body is organized into the thought-cells of the astral body.

C.C.ZAIN
"The astral body, which can live independent of the physical body, is composed of stellar substance which through the action of states of consciousness has been converted into psychoplasm

And just as the protoplasm of the physical body is organized into living cells so the psychoplasm of the astral body is organized into living intelligent stellar astral cells. These stellar cells, derived from states of consciousness, are like physical cells in that they represent definite compounds and are capable of limited intelligent work."