The man of spirituality and culture, on the other hand, may have perhaps twenty years of life in the astral world and a thousand in the heaven life.

One who is specially developed may reduce the astral life to a few days or hours and spend fifteen hundred years in heaven.
Not only does the length of these periods vary greatly, but the conditions in both worlds also differ widely.

The matter of which all these bodies are built is not dead matter but living, and that fact has to be taken into consideration.

The physical body is built up of cells, each of which is a tiny separate life animated by the Second Outpouring, which comes forth from the Second Aspect of the Deity.

These cells are of varying kinds and fulfil various functions, and all these facts must be taken into account if the man wishes to understand the work of his physical body and to live a healthy life in it.
The same thing applies to the astral and mental bodies.