Embryo Project Encyclopedia Articles

Wilhelm Roux was a nineteenth-century experimental embryologist who was best known for pioneering Entwicklungsmechanik, or developmental mechanics. Roux was born in Jena, Germany, on 9 June 1850, the only son of Clotilde Baumbach and a university fencing master, F. A. Wilhelm Ludwig Roux. Roux described himself as an aloof child, but when he was fourteen he cultivated a passion for science that was encouraged by the director at Oberrealschule in Meiningen. Roux attended the University of Jena in 1869, but his education was halted after the first year because of his service in the military during the Franco-Prussian War. When he returned from the war, he continued to take classes and was admitted into the University of Jena medical faculty. He passed his medical examination in 1877 and became a licensed doctor.

Leonard Hayflick studied the processes by which cells age during the twentieth and twenty-first centuries in the United States. In 1961 at the Wistar Institute in the US, Hayflick researched a phenomenon later called the Hayflick Limit, or the claim that normal human cells can only divide forty to sixty times before they cannot divide any further. Researchers later found that the cause of the Hayflick Limit is the shortening of telomeres, or portions of DNA at the ends of chromosomes that slowly degrade as cells replicate. Hayflick used his research on normal embryonic cells to develop a vaccine for polio, and from HayflickÕs published directions, scientists developed vaccines for rubella, rabies, adenovirus, measles, chickenpox and shingles.

Gavin de Beer was an English zoologist known for his contributions to evolution and embryology, in particular for showing the inadequacy of the germ layer theory as it was then proposed. He was born in London, England, on 1 November 1899, but was raised for his first thirteen years in France where his father worked for a telegraph company. He entered Magdalen College, Oxford, in 1917 but his studies were soon interrupted by World War I. After serving in the military, he returned to Oxford where he studied under Edwin Goodrich. He graduated in 1922 but stayed on as a fellow of Merton College and to teach in the Zoology Department. He was the Jenkinson Memorial Lecturer between 1926 and 1938.

Rudolf Carl Virchow lived in nineteenth century Prussia, now Germany, and proposed that omnis cellula e cellula, which translates to each cell comes from another cell, and which became and fundamental concept for cell theory. He helped found two fields, cellular pathology and comparative pathology, and he contributed to many others. Ultimately Virchow argued that disease is caused by changes in normal cells, also known as cellular pathology.

Hilde Proscholdt Mangold was a doctoral student at the Zoological Institute at the University of Freiburg in Freiburg, Germany, from 1920-1923. Mangold conducted research for her dissertation 'On the Induction of Embryonic Primordia by Implantation of Organizers from Different Species' ('Ueber Induktion von Embryonanlagen durch Implantation artfremder Organisatoren'), under the guidance of Hans Spemann, a professor of zoology at the University of Freiburg. The dissertation was the culmination of five experiments on three species of newt embryos, of the genus Triton (presently, Triturus), performed during the summers of 1921 and 1922, which resulted in a confirmation of Spemann's organizer concept. Spemann and Mangold published the dissertation in a 1924 edition of Roux's Archives for Microscopic Anatomy and Developmental Mechanics (Roux's Archiv fur Mikroskopische Anatomie und Entwicklungsmechanik)."

Thomson, et al. v. Thompson, et al. was a lawsuit filed in the United States District Court for the District of Columbia on 8 May 2001 as Civil Action Number 01-CV-0973. This lawsuit was filed in hopes of gaining injunctive relief against a moratorium on the federal funding of stem cell research. The plaintiffs in the case were seven prominent scientists who performed embryonic stem cell research and three patients: James Thomson, Roger Pedersen, John Gearhart, Douglas Melton, Dan Kaufman, Alan Trounson, Martin Pera, Christopher Reeve, James Cordy, and James Tyree. The suit was filed against Tommy G. Thompson in his official capacity as Secretary of the Department of Health and Human Services; Ruth Kirschstein in her official capacity as Acting Director of the National Institutes of Health; the Department of Health and Human Services (HHS); and the National Institutes of Health (NIH). The plaintiffs argued that by illegally delaying and withholding federal funds for stem cell research, the defendants were causing irreparable harm to research and development of potential therapies for patients.There was also concern about potentially preventing young researchers from entering the field, and restricting the sharing of discoveries between scientists that federal funding of scientific research fosters.

Victor Jollos studied fruit flies and microorganisms in Europe and the US, and he introduced the concept of Dauermodifikationen in the early 1900s. The concept of Dauermodifikationen refers to environmentally-induced traits that are heritable for only a limited number of generations. Some scientists interpreted the results of Jollos's work on Paramecium and Drosophila as
evidence for cytoplasmic inheritance. Jollos was forced to emigrate from Germany to the United States due to anti-semitic government policies in the early 1930s. Nevertheless, his work on Dauermodifikationen remained central to theoretical discourse among German zoologists concerning heredity, development, and evolution.

Petr Kropotkin proposed the theory of Pleistocene ice age, alternative theories of evolution based on embryology, and he advocated anarchist and communist social doctrines in Europe during the nineteenth and twentieth centuries. He traveled in eastern Siberia and Manchuria from 1863 until 1867, and his subsequent publications about that area's geography became authoritative until the middle of the twentieth century. Kropotkin argued that his geographic and geologic observations in Asia, Finland, Sweden, and Canada, supported the theory of Pleistocene continental glaciation, often called the ice age. He was one of the first to study the ancient geography and climate of the Quaternary period, which spans from 2.5 million years ago until the present. Around the turn of the nineteenth century, Kropotkin offered what he said were complementary amendments to Charles Darwin's 1859 theory of evolution by natural selection. Kropotkin employed a variety of arguments from natural history, embryology, and geography to support his theory of mutual aid, which he argued was a positive mechanistic addition to the theory of evolution.

Friedrich Tiedemann studied the anatomy of humans and animals in the nineteenth century in Germany. He published on zoological subjects, on the heart of fish, the anatomy of amphibians and echinoderms, and the lymphatic and respiratory system in birds. In addition to his zoological anatomy, Tiedemann, working with the chemist Leopold Gmelin, published about how the digestive system functioned. Towards the end of his career Tiedemann published a comparative anatomy of the brains of white Europeans, black Africans, and Orangutans, in which he argued that there were no appreciable differences between the structure of the brains of blacks, women, and white European men that would suggest they were intellectually different. Tiedemann also researched the embryonic development of the brain and circulatory systems of human fetuses.

Julius von Sachs helped establish plant physiology through his experiments in latter nineteenth-century Germany. Sachs infused the inchoate discipline of plant physiology with experimental techniques and a mechanistic stance, both of which cemented his place as one of the discipline s founders. Sachs trained a generation of plant physiologists, and his stress on experimentation and mechanism influenced biologists in other disciplines, especially embryologist Jacques Loeb.