In the mineral kingdom we include not only what are usually called minerals, but also liquids, gases and many etheric substances the existence of which is unknown to western science. 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 When mineral evolution is completed, the life has withdrawn itself again into the astral world, but bearing with it all the results obtained through its experiences in the physical.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 The attainment of this level is the sign that it has withdrawn itself still further, and is now working from the lower mental world.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. In the vegetable kingdom, for example, the life-force might commence its career by occupying grasses or mosses and end it by ensouling magnificent forest trees. In the animal kingdom it might commence with mosquitoes or with animalculæ, and might end with the finest specimens of the mammalia. The whole process is one of steady evolution from lower forms to higher, from the simpler to the more complex. But what is evolving is not primarily the form, but the life within it. The forms also evolve and grow better as time passes; but this is in order that they may be appropriate vehicles for more and more advanced waves of life. When the life has reached the highest level possible in the animal kingdom, it may then pass on into the human kingdom, under conditions which will presently be explained.