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Embryos under the Microscope

Embryos under the Microscope

Copyright Date: 2014
Published by: Harvard University Press
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  • Book Info
    Embryos under the Microscope
    Book Description:

    Jane Maienschein examines how understanding of embryos evolved from the speculations of natural philosophers to bioengineering, with its life-enhancing therapies. She shows that research on embryos has always seemed promising to some but frightening to others, and makes the case that public understanding must be informed by scientific findings.

    eISBN: 978-0-674-36972-6
    Subjects: Developmental & Cell Biology, Health Sciences, History of Science & Technology, General Science, Political Science

Table of Contents

  1. Front Matter
    (pp. i-iv)
  2. Table of Contents
    (pp. v-vi)
  3. Preface
    (pp. vii-xii)
  4. 1 Recurring Questions, Seeing and Believing
    (pp. 1-27)

    Looking at embryos without a microscope does not show much by itself. Human embryos are too tiny to see at all other than as teensy specks in a laboratory dish at a fertility clinic. Frog embryos are large enough to see, but not with much detail: a big egg cell divides into other cells and then gives rise to a tadpole, which swims around for a while then metamorphoses through a process of changing shape into a frog. Chick embryos are inside eggshells. Other species form in similar ways, and without a microscope to magnify the cells, we cannot see...

  5. 2 Hypothetical and Observed Embryos with Microscopes at Work
    (pp. 28-65)

    We go back here to that initial time when people could not actually see much and had to imagine what happened in the earliest stages of development. This chapter provides a brief description of the first two historical periods of embryo studies: the hypothetical and observed embryos, examining what those periods entailed. One interpretive theme runs throughout, offering two ways of imagining what was going on with embryos: epigenesis versus preformationism. In general, these two ways of imagining development remained distinct and non-overlapping. Indeed, during most of history the two were in direct competition. Yet it is possible to hold...

  6. 3 Experimental Embryos in the Laboratory
    (pp. 66-104)

    Experimentation made possible an additional source of information and interpretation to take the observer beyond what he (the researchers were still mostly male well into the twentieth century) could normally see. The distinguished historian of science Garland Allen has addressed the move toward explicitly experimental approaches to biology in his textbookLife Science in the Twentieth Century.¹ He gives us a look not just at the separate specialties of the life sciences, but also at the idea (and ideal) of life science as a whole with many parts that work together. Furthermore, Allen puts forth the interpretation that the new...

  7. 4 Inherited, Evolved, and Computed Embryos
    (pp. 105-139)

    So far, we have focused on the history of people looking at embryos and describing what they saw. They have experimented with embryos, developed ways to look inside them using microscopes and other tools and techniques to see more detailed structures, and then have tried to make sense of what they have seen. Yet the focus has remained largely on the physical object, with discussions about causation based on understanding how one stage gives rise to the next through material and largely structural or sometimes physiological changes.

    Many of the descriptive and experimental embryologists we have discussed at the turn...

  8. 5 The Visible Human Embryo
    (pp. 140-175)

    Within the context of changing theoretical interpretations and research to understand all kinds of animal embryos from many points of view, the human embryo finally became visible. As in other mammals, the developing human organism remains inside the mother until it is born. Historically, the only way to study it had been indirectly, until 1978 when the embryo came out, so to speak. As we know, researchers had seen early-stage human embryos before, as represented in the Carnegie collection, but these embryos were always dead, and many had been abnormal and spontaneously aborted. In 1978, thanks to the physician Patrick...

  9. 6 The Idea of Engineered and Constructed Embryos
    (pp. 176-215)

    Engineering embryos to manipulate cells into what we want them to be or to do is an old idea. Only recently has the idea of constructing embryos out of nonembryonic materials or parts begun to seem possible. Yet recent ideas of constructing embryos and thereby organisms from scratch are an extension of suggestions about engineering and experimental manipulation already laid out much earlier. This chapter looks at the history of engineering attempts, when researchers first began to imagine that they could manipulate embryos to suit their interests.

    The story starts with Jacques Loeb and his engineering ideas, then proceeds to...

  10. 7 Constructing Embryos for Society, Stem Cells in Action
    (pp. 216-252)

    In the past few decades, embryos have received more media attention than during the preceding millennia. Previously imagined prospects for controlling life now have come true in many different ways that involve embryos. By the time this book appears in print, still more new discoveries and new questions undoubtedly will have emerged, some of which will confront us with what seem to be new questions or with calls for new kinds of answers. Yet those discoveries, questions, and answers all exist in an historical context. Reflecting on each new development in the light of history can inform our understanding of...

  11. 8 Constraints and Opportunities for Construction
    (pp. 253-273)

    What we know about developing embryos has increased tremendously, with increasing speed, as we have seen in the previous chapters. Stem cell research and regenerative biology generally are already leading to use-inspired research and medical applications. Yet the logical extension of Jacques Loeb’s vision of not just understanding but actually controlling life is only beginning to come into reality. So far, we have seen a great deal of observing, experimenting, using microscopes to see more detail, extending research on cells into glass dishes with culture media, and imagining ways to use stem cells to replace lost function.

    Loeb would probably...

  12. Therefore …
    (pp. 274-288)

    This book recounts a history of looking at embryos through microscopes and other techniques, and thereby gaining a growing understanding of their biological reality. Looking at the embryo reveals a complex interactive system, which adapts to changing environmental conditions. It is worthwhile to review the biological details here quickly, because getting the facts right is very important for grounding policy decisions. Even though much of the history presented in this book has been drawn from the study of a wide variety of animals, let us now focus on humans alone.

    Each cell is highly structured: the cytoplasm surrounds a nucleus...

  13. Notes
    (pp. 289-312)
  14. Acknowledgments
    (pp. 313-316)
  15. Index
    (pp. 317-336)