We may take out another tumblerful of water from that bucket, but we can never again get exactly the same tumblerful after it has once been mingled with the rest.  Every tumblerful taken from that bucket in the future will contain some traces of the colouring or flavouring put into each tumbler whose contents have been returned to the bucket.  Just so the qualities developed by the experience of a single lion will become the common property of all lions who are in the future to be born from that group-soul, though in a lesser degree than that in which they existed in the individual lion who developed them.

That is the explanation of inherited instincts; that is why the duckling which has been hatched by a hen takes to the water instantly without needing to be shown how to swim; why the chicken just out of its shell will cower at the shadow of a hawk; why a bird which has been artificially hatched, and has never seen a nest, nevertheless knows how to make one, and makes it according to the traditions of its kind.

Lower down in the scale of animal life enormous numbers of bodies are attached to a single group-soul—­countless millions, for example, in the case of some of the smaller insects; but as we rise in the animal kingdom the number of bodies attached to a single group-soul becomes smaller and smaller, and therefore the differences between individuals become greater.

Thus the group-souls gradually break up.  Returning to the symbol of the bucket, as tumbler after tumbler of water is withdrawn from it, tinted with some sort of colouring matter and returned to it, the whole bucketful of water gradually becomes richer in colour.  Suppose that by imperceptible degrees a kind of vertical film forms itself across the centre of the bucket, and gradually solidifies itself into a division, so that we have now a right half and a left half to the bucket, and each tumblerful of water which is taken out is returned always to the same section from which it came.

Then presently a difference will be set up, and the liquid in one half of the bucket will no longer be the same as that in the other.  We have then practically two buckets, and when this stage is reached in a group-soul it splits into two, as a cell separates by fission.  In this way, as the experience grows ever richer, the group-souls grow smaller but more numerous, until at the highest point we arrive at man with his single individual soul, which no longer returns into a group, but remains always separate.

One of the life-waves is vivifying the whole of a kingdom; but not every group-soul in that life-wave will pass through the whole of that kingdom from the bottom to the top.  If in the vegetable kingdom a certain group-soul has ensouled forest trees, when it passes on into the animal kingdom it will omit all the lower stages—­that is, it will never inhabit insects or reptiles, but will begin at once at the level of the lower mammalia.  The insects and reptiles will be vivified by group-souls which have for some reason left the vegetable kingdom at a much lower level than the forest tree.  In the same way the group-soul which has reached the highest levels of the animal kingdom will not individualize into primitive savages, but into men of somewhat higher type, the primitive savages being recruited from group-souls which have left the animal kingdom at a lower level.