Embryos in Wax: Models from the Ziegler Studio is a history of embryo wax modeling written by science historian Nick Hopwood. Published by the Whipple Museum of the History of Science University of Cambridge and the Institute of the History of Medicine University of Bern, 2002, the book, like the wax models, helps exemplify the visual and material culture of science. The first half of the book describes the modeling work of Germany's Adolf and son Friedrich Ziegler during the rise of developmental embryology from 1850 to 1920, a time when embryology's practitioners needed educational aids that could help teach students in laboratories and lay persons in public lectures. Three-dimensional wax models provided just this visual aid.

Three-dimensional anatomical models have long been essential to the learning of science and lend a sense of "control" to those practicing in the field. As the development of embryology grew in importance during the late 1800s, so did the need for models to show intricate details of embryos. Embryologists such as Wilhelm His, Ernst Haeckel, and Oscar Hertwig all initially constructed their own wax models of embryos but later handed over the modification and reproduction of their models to various "plastic artists." The most renowned among these artists was Adolf Ziegler.

Alan Mathison Turing was a British mathematician and computer scientist who lived in the early twentieth century. Among important contributions in the field of mathematics, computer science, and philosophy, he developed a mathematical model of morphogenesis. This model describing biological growth became fundamental for research on the process of embryo development.

The scientific field of embryology experienced great growth in scope and direction in Germany from approximately 1850 to 1920. During this time, Adolf Ziegler and his son Friedrich crafted hundreds of wax embryo models, representing a shift in how embryos were viewed and used. Their final products, whether human or trout embryos, showcased the now lost collaboration between wax modeling artists and embryologists.

Cellular automata (CA) are mathematical models used to simulate complex systems or processes. In several fields, including biology, physics, and chemistry, CA are employed to analyze phenomena such as the growth of plants, DNA evolution, and embryogenesis. In the 1940s John von Neumann formalized the idea of cellular automata in order to create a theoretical model for a self-reproducing machine. Von Neumann's work was motivated by his attempt to understand biological evolution and self-reproduction.

Osborne O. Heard was a noted Carnegie embryological model maker for the Department of Embryology at The Carnegie Institute of Washington (CIW), Baltimore, Maryland. Heard was born in Frederick, Maryland, on 21 November 1890. His father died while Heard and his three brothers were quite young. Heard attended night school at the Maryland Institute of Art and Design where he studied sculpting and patternmaking. While working as a patternmaker for the Detrick and Harvey Machine Company, Heard made models of tools using a variety of materials such as wood, plastic, and plaster of Paris. These models were then handed over to a mold maker to form a casting. Heard's work came to the attention of Franklin Paine Mall, the first director of the CIW's Embryology Department. Mall persuaded Heard to leave the machine company and to continue his craft at the Carnegie Institute. Hired in 1913, Heard remained an employee of the department for forty-two years, making hundreds of wax and plaster embryo models and contributing to several improvements in reconstruction technology.

The French flag model represents how embryonic cells receive and respond to genetic information and subsequently differentiate into patterns. Created by Lewis Wolpert in the late 1960s, the model uses the French tricolor flag as visual representation to explain how embryonic cells can interpret genetic code to create the same pattern even when certain pieces of the embryo are removed. Wolpert's model has provided crucial theoretical framework for investigating universal mechanisms of pattern formation during development.

In March 1999 Bradley Richard Smith, a professor at the University of Michigan, unveiled the first digital magnetic resonance images of human embryos. In his article "Visualizing Human Embryos for Scientific American," Smith displayed three-dimensional images of embryos using combinations of Magnetic Resonance Microscopy (MRM), light microscopy, and various computer editing. He created virtual embryo models that it is possible to view as dissections, animations, or in their whole 3D form. Smith's images constitute a new way of visualizing embryos. They served to help students, researchers, clinicians and the general public interested in the study and investigation of human embryonic development.

In 1952 the article "The Chemical Basis of Morphogenesis" by the British mathematician and logician Alan M. Turing was published in Philosophical Transactions of the Royal Society of London. In that article Turing describes a mathematical model of the growing embryo. He uses this model to show how embryos develop patterns and structures (e.g., coat patterns and limbs, respectively). Turing's mathematical approach became fundamental for explaining the developmental process of embryos. In the 1970s, for instance, scientists Alfred Gierer and Hans Meinhardt used Turing's model to work out how the patterns on seashells develop.

Anatomical models have always been a mainstay of descriptive embryology. As the training of embryologists grew in the late 1800s, so too did the need for large-scale teaching models. Embryo wax models, such as those made by Adolf Ziegler and Gustav Born, were popular in the latter part of the nineteenth century and the early twentieth century as a way to visualize, in three dimensions, the fine detail of embryos without the aid of a microscope. While these models were found in many university laboratories, museums of science, and even expositions and world's fairs, they were anything but easy to make or obtain. Wax modeling required skill, patience, and specialized tools. Small laboratories with only one or two embryologists often found the prospect of wax modeling too laborious, too difficult, and too expensive to make the pursuit worthwhile. As an alternative, Susanna Phelps Gage, an embryologist at Cornell University, perfected a technique of using stacks of absorbent blotting paper rather than stacks of wax plates for constructing embryo models. She first demonstrated her blotting paper method to other embryologists at the annual meeting of the Association of American Anatomists in 1905 and later at the International Zoological Congress, held in Boston in August 1907.

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