PART I.--THE INDIVIDUAL ORGANISM WITH REGARD TO FORM AND METABOLISM

*A.* ELEMENTARY MORPHOGENESIS--

Evolutio and Epigenesis in the old Sense 25 The Cell 27 The Egg: its Maturation and Fertilisation 31 The First Developmental Processes of Echinus 33 Comparative Embryology 44 The First Steps of Analytical Morphogenesis 45 The Limits of Pure Description in Science 50

*B.* EXPERIMENTAL AND THEORETICAL MORPHOGENESIS--

1. THE FOUNDATIONS OF THE PHYSIOLOGY OF DEVELOPMENT. “EVOLUTIO” AND “EPIGENESIS” 52

The Theory of Weismann 52 Experimental Morphology 56 The Work of Wilhelm Roux 58 The Experiments on the Egg of the Sea-urchin 59 On the Intimate Structure of the Protoplasm of the Germ 65 On some Specificities of Organisation in Certain Germs 70 General Results of the First Period of “Entwickelungsmechanik” 71 Some New Results concerning Restitutions 74

2. ANALYTICAL THEORY OF MORPHOGENESIS 76

α. THE DISTRIBUTION OF MORPHOGENIC POTENCIES 76

Prospective Value and Prospective Potency 76 The Potencies of the Blastomeres 79 The Potencies of Elementary Organs in General 80 Explicit and Implicit Potencies: Primary and Secondary Potencies 83 The Morphogenetic Function of Maturation in the Light of Recent Discoveries 85 The Intimate Structure of Protoplasm: Further Remarks 88 The Neutrality of the Concept of “Potency” 89

β. THE “MEANS” OF MORPHOGENESIS 89

β′. The Internal Elementary Means of Morphogenesis 90

Some Remarks on the Importance of Surface Tension in Morphogenesis 91 On Growth 93 On Cell-division 94

β″. The External Means of Morphogenesis 95

The Discoveries of Herbst 96

γ. THE FORMATIVE CAUSES OR STIMULI 99

The Definition of Cause 99 Some Instances of Formative and Directive Stimuli 102

δ. THE MORPHOGENETIC HARMONIES 107

ε. ON RESTITUTIONS 110

A few Remarks on Secondary Potencies and on Secondary Morphogenetic Regulations in General 110 The Stimuli of Restitutions 113

3. THE PROBLEM OF MORPHOGENETIC LOCALISATION: THE THEORY OF THE HARMONIOUS-EQUIPOTENTIAL SYSTEM--FIRST PROOF OF THE AUTONOMY OF LIFE 118

The General Problem 118 The Morphogenetic “System” 119 The “Harmonious-equipotential System” 122 Instances of “Harmonious-equipotential Systems” 126 The Problem of the Factor *E* 132 No Explanation offered by “Means” or “Formative Stimuli” 132 No Explanation offered by a Chemical Theory of Morphogenesis 134 No Machine Possible Inside the Harmonious Systems 138 The Autonomy of Morphogenesis proved 142 “Entelechy” 143 Some General Remarks on Vitalism 145 The Logic of our First Proof of Vitalism 146

4. ON CERTAIN OTHER FEATURES OF MORPHOGENESIS ADVOCATING ITS AUTONOMY 150

Harmonious-equipotential Systems formed by Wandering Cells 151 On Certain Combined Types of Morphogenetic Systems 153 The “Morphaesthesia” of Noll 157 Restitutions of the Second Order 158 On the “Equifinality” of Restitutions 159 Remarks on “Retro-Differentiation” 163

*C.* ADAPTATION--

INTRODUCTORY REMARKS ON REGULATIONS IN GENERAL 165

1. MORPHOLOGICAL ADAPTATION 168

The Limits of the Concept of Adaptation 168 Adaptations to Functional Changes from Without 172 True Functional Adaptation 176 Theoretical Conclusions 179

2. PHYSIOLOGICAL ADAPTATION 184

Specific Adaptedness *not* “Adaptation” 186 Primary and Secondary Adaptations in Physiology 188 On Certain Pre-requisites of Adaptations in General 189 On Certain Groups of Primary Physiological Adaptations 190

General Remarks on Irritability 190 The Regulation of Heat Production 193 Primary Regulations in the Transport of Materials and Certain Phenomena of Osmotic Pressure 194 Chromatic Regulations in Algae 197 Metabolic Regulations 198

Immunity the only Type of a Secondary Physiological Adaptation 204 No General Positive Result from this Chapter 209 A few Remarks on the Limits of Regulability 212

*D.* INHERITANCE. SECOND PROOF OF THE AUTONOMY OF LIFE--

The Material Continuity in Inheritance 214 On Certain Theories which Seek to Compare Inheritance to Memory 216 The Complex-Equipotential System and its Rôle in Inheritance 219 The Second Proof of Life-Autonomy. Entelechy at the Bottom of Inheritance 224 The Significance of the Material Continuity in Inheritance 227 The Experimental Facts about Inheritance 228 The Rôle of the Nucleus in Inheritance 233 Variation and Mutation 237

*CONCLUSIONS FROM THE FIRST MAIN PART OF THESE LECTURES* 240