Living Matter: Its Functions 24 Its Substance 27 Its Structure 28 CHAPTER III De Minimis Growth and Development 32 Development a Cell-problem 33 The Mechanical Conception of Life 34 The Cell and its Structure 38 Cell-division and Heredity 40 Reproductive Cells and Body-cells 45 The Origin of Conjugation 46 The Mechanism of Conjugation 51 Significance of Elementary Vital Processes 59 Adaptability, a Fundamental Character of Life 63 CHAPTER IV The Mechanical Theory of Evolution: the Darwin-Lamarck Explanation The Fixity of Species, how Maintained 66 The Mutability of Species 67 Lamarck’s Explanation of the Origin of Species 68 Natural Selection of Innate Variations 72 Difficulties of Lamarckism 77 Need of a deeper Explanation 89 CHAPTER V The Mechanical Theory of Evolution: the Darwin-Weismann Explanation Lamarck, or ‘Metaphysics’? 91 Weismann’s Escape 93 The Struggle among the Determinants 95 Chance-Variations and Co-adaptation 97 Other Difficulties of the Chance-Variation Theory 99 Natural Selection 103 Impossible before Competition Existed 104 Co-operation and Competition 104 Protective Mimicry, Inexplicable by Chance-Variations and Natural Selection 106 Innate Capacities of Life 109 Outline of Preceding Arguments 111 CHAPTER VI The Directive Theory of Evolution Nature’s Power of Response 115 Reinke’s Theory of Dominants 120 Cases of their Action in Evolution 123 Law and Directivity 128 Intelligence and Directivity 130 The Analogy of Social Evolution 131