All the matter of which we know anything is living matter, and the life which it contains is always evolving.

When it has reached the central point of the mineral stage the downward pressure ceases, and is replaced by an upward tendency; the outbreathing has ceased and the indrawing has begun.
When mineral evolution is completed, the life has withdrawn itself again into the astral world, but bearing with it all the results obtained through its experiences in the physical.

At this stage it ensouls vegetable forms, and begins to show itself much more clearly as what we commonly call life--plant-life of all kinds; and at a yet later stage of its development it leaves the vegetable kingdom and ensouls the animal kingdom.

The attainment of this level is the sign that it has withdrawn itself still further, and is now working from the lower mental world.

In order to work in physical matter from that mental world it must operate through the intervening astral matter; and that astral matter is now no longer part of the garment of the group-soul as a whole, but is the individual astral body of the animal concerned, as will be later explained.
In each of these kingdoms it not only passes a period of time which is to our ideas almost incredibly long, but it also goes through a definite course of evolution, beginning from the lower manifestations of that kingdom and ending with the highest.