hold sway throughout. In framing my arbitrary definitions I can say either that the dead is living, or that the living does not differ essentially from the dead. In the chain of living things man comes from the primitive cell, the moneron. This in its turn has developed from something earlier—“naturally” developed. The very idea of life forces us to seek the predecessors of the monera. Hence we speak of “spontaneous generation,” as what was dead according to our ordinary use of language has begun to live. In point of fact it is merely development of a unified whole. There is no gap, no leap, no act that is not natural. The dead and the living never were really antithetic. The insistent statement that not only does the living approach the inorganic, but the inorganic approaches the living, is quite “Haeckelian.” The study of the “life” of crystals is one of the best parts of the book. Later generations will appreciate it. We are much too narrow to-day when we merely reflect that life, even the life of man, can be traced by evolution down to what we call dead matter. We forget that this “matter” is already high, since it potentially contains life, and even man, the crown of life. Many people imagine that the derivation of man from “dead matter” is equal to turning a king into a beggar. They do not reflect that, on the other hand, a beggar is turned into a king. When I say that life arose one day out of the inorganic, or that a crystal was turned into a cell, my statement really involves the complementary truth that the inorganic potentially contains life in itself. Otherwise we have the old miracle over again of something being produced out of nothing, in spite of our spontaneous generation. Haeckel has always been clear on this point. His later studies of the soul of the atom and the plastidule only carry out the absolutely logical treatment of the question that we find in these chapters of the first volume of the _Morphology_. Incidentally the question is raised whether the plant or the animal was evolved first. Animal and plant are, of course, not rigidly distinct from each other. They are only the two great branches of the Darwinian evolution of living forms, and are united at the bottom, however much they diverge above. Gegenbaur had represented this years before (1860) in a figure that Haeckel quotes in his _Monograph on the Radiolaria_ in 1862. The whole kingdom of living things must be conceived “as a connected series, within which we find two lines diverging from a common centre and representing a gradual differentiation and development of organisation.” The terminal points of these lines (the highest plant and the highest animal) are very different from each other, but the difference gradually disappears as we go back towards the common centre, and the lowest stages in each kingdom can hardly be distinguished from each other. For these lowest stages Haeckel now carries out a plan that very quickly forced itself on him.