We are reminded of Virchow’s speech, and how “consciousness” was dragged into the debate on the cell-state. What psychological perspectives are opened out by this doctrine of individuality! Each form-unity, each single individuality in the series, with a soul! Souls combining for common action, and forming higher psychic unities! There is no detail in Haeckel’s whole life-work in which he speaks more boldly and freely and philosophically than he does here. His lucid treatment raises to a higher stage a philosophic question that has occupied thinkers for ages. That is the third book. The fourth takes up a different subject. Let us adopt in organic morphology this wonderful theory of individuality, the theory of stages within the form. Then let us turn to consider impartially the vast multitude of living forms. How can we now arrange this infinite confusion by merely looking at it? Artificial classification has attempted it a hundred times, and always without success. On this side there is only one way to proceed—the mathematical. I study them with strictly mathematical figures. I determine their axes, and the mathematical aspects of their forms. Possibly that will give a practical result; the only kind of artificial system that can be accommodated with the Darwinian theory, and perhaps render it assistance by the sharpness of its lines. Does it answer? Take a crystal, a specimen from inorganic morphology. The description of it is susceptible of a strictly mathematical form. Now take a star-fish, a worm, a human being. We find that even these organic structures have a mysterious relation at bottom to certain mathematical, stereometric forms. We might almost say, to certain forms of human thought. Everything in the organic world is in a state of flux. But through the whole moving stream we can trace the outline of one stable element, something like a mathematical idea. A sort of Platonism of the living forms vaguely takes shape. Haeckel speaks of lines, axes, circles, radii, and all kinds of rhythmic structures. It does seem that the countless individual forms of living things fit into a scheme of a limited number of mathematical forms. Strictly speaking this is not a real morphology of living things. We only find these clear and rigid forms schematically in the wild profusion of forms of the protists, plants, and animals. They are only a reminiscence of the laws of the purely inorganic, which the eye of the observer just detects as the lowest stratum. Hence Haeckel calls this section the “promorphology” of organisms.