"Glory to the science of embryology!" So Johannes Holtfreter closed his letter to this editor when he granted permission to publish his article in this volume. And glory there is: glory in the phenomenon of animals developing their complex morphologies from fertilized eggs, and glory in the efforts of a relatively small group of scientists to understand these wonderful events. Embryology is unique among the biological disciplines, for it denies the hegemony of the adult and sees value (indeed, more value) in the stages that lead up to the fully developed organism. It seeks the origin, and not merely the maintenance, of the body. And if embryology is the study of the embryo as seen over time, the history of embryology is a second-order derivative, seeing how the study of embryos changes over time. As Jane Oppenheimer pointed out, "Sci ence, like life itself, indeed like history, itself, is a historical phenomenon. It can build itself only out of its past. " Thus, there are several ways in which embryology and the history of embryology are similar. Each takes a current stage of a developing entity and seeks to explain the paths that brought it to its present condition. Indeed, embryology used to be called Entwicklungsgeschichte, the developmental history of the organism. Both embryology and its history interpret the interplay between internal factors and external agents in the causation of new processes and events.

Inhalt
1 · The Rise of Classical Descriptive Embryology.- 1. Introduction.- 2. Descriptive Embryology in the Baltic Periphery.- 3. Christian Pander.- 4. Karl Ernst von Baer.- 5. Heinrich Rathke.- 6. A New Theoretical Framework at Mid-Century.- 7. Evolution and Development.- 8. Specificity of the Germ Layers.- 9. Conclusion.- Notes and References.- 2 · Laurent Chabry and the Beginnings of Experimental Embryology in France.- 1. Introduction.- 2. E. Geoffroy Saint-Hilaire.- 3. C. Dareste.- 4. Stanislas Warynski and Hermann Fol.- 5. Laurent Chabry.- 6. Edwin Grant Conklin, Albert Dalcq, and Oscar Hertwig.- 7. Conclusions.- Notes and References.- 3 · The Origins of Entwicklungsmechanik.- 1. Introduction.- 2. Foundations of Entwicklungsmechanik.- 3. Experimental Embryology.- 4. Responses.- Notes and References.- 4 · Curt Herbst's Contributions to the Concept of Embryonic Induction.- 1. Introduction.- 2. Curriculum Vitae.- 3. Personalia.- 4. Opera Magna.- 5. Obiter Dicta.- 6. Ab Origine.- Notes and References.- 5 · Spemann Seen through a Lens.- 1. Introduction.- 2. Early Years: The Search for a Problem of General Interest.- 3. Lens Induction: A Paradigm for Vertebrate Cell Determination.- 4. Determination at Gastrula Stages: Application of the Lens-Induction Paradigm to the Organizer Experiments.- 5. Postscript: A Modern Perspective.- Notes and References.- 6 · Reminiscenses on the Life and Work of Johannes Holtfreter.- 1. Editor's Note.- 2. Foreword.- 3. Reminiscence.- References.- 7 · The Conceptual and Experimental Foundations of Vertebrate Embryonic Cell Adhesion Research.- 1. Introduction.- 2. The Invertebrate Zoological Roots of Intercellular Cell Adhesion Studies.- 3. The Recognition of Differential Cell Adhesion as a Central Mechanism of Morphogenesis.- 4.Qualitative and Quantitative Quarrels over the Quintessence of Cell Adhesion.- 5. Immunological Approaches to the Analysis of Cell Adhesion.- 6. The Role of Calcium in Cell Adhesion.- 7. Epilogue: From the Embryo to the Gene and Back.- Notes and References.- 8 · The Philosophical Background of Joseph Needham's Work in Chemical Embryology.- 1. Introduction.- 2. Joseph Henri Woodger and the Emancipation of Biology.- 3. Joseph Needham, 19251933: Mechanism, Organicism, and the Philosophical Status of Biochemistry.- 4. Process and Structure in the WoodgerNeedham Rapprochement: From Philosophical Misunderstandings toward a Theoretical Integration of Biochemistry, Embryology, and Logistics.- 5. Conclusions: The Philosophical and Social Context of Biochemical Embryology in the 1930s.- Notes and References.- 9 · Induction and the Origins of Developmental Genetics.- 1. Introduction: The Problem of Synthesis.- 2. Salome Gluecksohn-Schoenheimer and the Path from Experimental Embryology to Developmental Genetics.- 3. The Concrescence of Genetics and Development: C. H. Waddington.- Notes and References.- 10 · Boris Ephrussi and the Synthesis of Genetics and Embryology.- 1. Introduction.- 2. Early Embryological Studies.- 3. Beadle and Ephrussi on Drosophila Hormones.- 4. Ephrussi and Slonimski on Cytoplasmic Inheritance of Respiratory Competence in Yeast.- 5. Somatic Cell Genetics and the Return to Tissue Culture.- 6. Coda and Conclusion.- Notes and References.- 11 · Concepts of Organization: The Leverage of Ciliate Protozoa.- 1. A Discourse on Exceptions.- 2. Deconstructing the Germ Plasm.- 3. Revolt from Morphological Theories: Protests and Demonstrations.- 4. Weismannism under a New Banner: Geneticists versus Embryologists.- 5. Plasmagene Theory.- 6.Switching Concepts and Metaphors.- 7. Supramolecular Structure and Morphogenetic Fields.- 8. Concluding Remarks.- Notes and References.