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Edgar Allen (1892–1943)

Edgar Allen identified and outlined the role of female sex hormones and discovered estrogen in the early 1900s in the US. In 1923, Allen, through his research with mice, isolated the primary ovarian hormone, later renamed estrogen, from ovarian follicles and tested its effect through injections in the uterine tissues of mice. Allen’s work on estrogen, enabled researchers to further study hormones and the endocrine system.

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Subject: People

Antoni van Leeuwenhoek (1632-1723)

Antoni van Leeuwenhoek was born in Delft, the Netherlands, on 24 October 1632 to Margriet Jacobsdochter van den Berch and Philips Thooniszoon, both of whom were middle-class artisans. He attended grammar school in Warmond, and then temporarily moved to Benthuizen to live with relatives. Eventually Leeuwenhoek left for Amsterdam to work as a cloth merchant's apprentice. Returning to Delft, he married Barbara de Mey on 29 July 1654, and worked as a shopkeeper. The marriage resulted in five children, only one of whom, Maria, outlived Leeuwenhoek.

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Subject: People

Jan Swammerdam (1637-1680)

Jan Swammerdam, known as the founder of the preformation theory based on his extensive research on insect development, was born on 12 February 1637 in Amsterdam, the Netherlands, to Baertje Jans Corvers and Jan Jacobszoon Swammerdam. He began medical school on 11 October 1661 at the University of Leiden. A few of his classmates included Regnier de Graaf, Frederik Ruysch, Niels Stensen (Nicolaus Steno), and Robertus Padtbrugge. Padtbrugge would later join the East India Company and send Swammerdam exotic animals.

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Subject: People

Frederik Ruysch (1638-1731)

Frederik Ruysch made anatomical drawings and collected and preserved human specimens, many of which were infants and fetuses, in the Netherlands during the seventeenth and eighteenth centuries. Ruysch had many interests, including anatomy, botany, and medicine, and he discovered structures of the lymphatic system and of the eye. His collection of preserved human specimens were used as educational tools for his students and for other physicians, and they were displayed in a museum of his own making that was open to the public.

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Subject: People

Roy Chapman Andrews (1884-1960)

Roy Chapman Andrews traveled the world studying fossils, from mammals to dinosaurs, during the first half of the twentieth century. Andrews worked and collected fossil specimens for the American Museum of Natural History (AMNH) in New York City, New York. Throughout his career, Andrews collected bones of many animal species, including a previously unknown species of a horned, herbivorous dinosaur, later named Proceratops andrewsi in his honor. Andrews published widely read narratives about his travels and field experiences, such as On the Trail of Ancient Man and Across Mongolian Plains.

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Subject: People

Johannes Holtfreter (1901-1992)

Johannes Holtfreter made important discoveries about the properties of the organizer discovered by Hans Spemann. Although he spent much time away from the lab over many years, he was a productive researcher. His colleagues noted that the time he spent away helped revitalize his ideas. He is credited with the development of a balanced salt medium to allow embryos to develop; the discovery that dead organizer tissue retains inductive abilities; and the development of specification, competence, and distribution of fate maps in the developing frog embryo.

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Subject: People

Johann Friedrich Blumenbach (1752-1840)

In eighteenth century Germany, Johann Friedrich Blumenbach studied how individuals within a species vary, and to explain such variations, he proposed that a force operates on organisms as they develop. Blumenbach used metrical methods to study the history of humans, but he was also a natural historian and theorist. Blumenbach argued for theories of the transformation of species, or the claim that new species can develop from existing forms.

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Subject: People

Johann Gregor Mendel (1822-1884)

Johann Gregor Mendel studied plants and their patterns of inheritance in Austria during the nineteenth century. Mendel experimented with the pea plant, Pisum, and his publication, 'Versuche uber Pflanzenhybriden' (“Experiments on Plant Hybridization”), published in 1866, revolutionized theories of trait inheritance. Mendel’s discoveries relating to factors, traits, and how they pass between generations of organisms enabled scientists in the twentieth century to build theories of genetics.

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Subject: People

Regnier de Graaf (1641-1673)

Regnier de Graaf, a Dutch physician and anatomist, was born 30 July 1641 in Schoonhoven, the Netherlands. Though he published papers on both pancreatic and male reproductive anatomy, he is best known for his discovery of the mature ovarian follicles as well as his contributions to the general body of knowledge surrounding the female mammalian reproductive organs.

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Subject: People

Andreas Vesalius (1514–1564)

Andreas Vesalius, also called Andries van Wesel, studied anatomy during the sixteenth century in Europe. Throughout his career, Vesalius thoroughly dissected numerous human cadavers, and took detailed notes and drawings of his research. Compiling his research, Vesalius published an anatomy work titled De humani corporis fabrica libri septem (On the fabric of the human body in seven books). The Fabrica included illustrations of dissected men, women, and uteruses with intact fetuses.

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Subject: People

Johann Friedrich Meckel, the Younger (1781-1833)

Johann Friedrich Meckel studied abnormal animal and human anatomy in nineteenth century Germany in an attempt to explain embryological development. During Meckel's lifetime he catalogued embryonic malformations in multiple treatises. Meckel's focus on malformations led him to develop concepts like primary and secondary malformations, atavism, and recapitulation- all of which influenced the fields of medicine and embryology during the nineteenth and twentieth centuries.

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Subject: People

Nicolaas Hartsoeker (1656-1725)

Nicolaas Hartsoeker, a Dutch astronomer, optics manufacturer, and naturalist, was born 26 March 1656 in Gouda, Netherlands, and died 10 December 1725. His mother was Anna van der Mey and his father was Christiaan Hartsoeker, a prominent evangelical minister. His major contribution to embryology was his observations of human sperm cells, which he claimed to be the first to see under a microscope. His sketch of the homunculus, a tiny preformed human he believed to exist in the head of spermatazoa, is his lasting scientific legacy in the field of embryology.

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Subject: People

Jan Evangelista Purkyne (1787-1869)

Jan Evangelista Purkyne, also called Johannes or Johann Evangelist Purkinje, studied cells in the cerebellum, fibers of the heart, subjective visual phenomenon, and germinal vesicle, in eastern Europe during the early nineteenth century. His investigations provided insights into various mechanisms and structures of the human body. Purkyne introduced techniques for decalcification of bones and teeth, embedding of tissue specimens, and eye examinations.

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Subject: People

Wilhelm Friedrich Phillip Pfeffer (1845-1920)

Wilhelm Friedrich Phillip Pfeffer studied plants in Germany during the late nineteenth and early twentieth centuries. He started his career as an apothecary, but Pfeffer also studied plant physiology, including how plants move and react to changes in light, temperature, and osmotic pressure. He created the Pfeffer Zelle apparatus, also known as the Pfeffer Cell, to study osmosis in plants. PfefferÕs experiments led to new theories about the structure and development of plants.

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Subject: People

Abraham Trembley (1710-1784)

Abraham Trembley's discovery of the remarkable regenerative capacity of the hydra caused many to question their beliefs about the generation of organisms. Born 3 September 1710 to a prominent Geneva family, Trembley studied at the Calvin Institute, now the University of Geneva, where he completed his thesis on calculus. He went on to become tutor for Count William Bentinck's two sons, and it was while teaching the boys natural history that Trembley came across a strange organism in a sample of pond water.

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Subject: People

Wilhelm His, Sr. (1831-1904)

Wilhelm His, Sr. was born on 9 July 1831 in Basel, Switzerland, to Katharina La Roche and Eduard His. He began his medical studies at Basel in 1849 and later transferred to the University of Bern during the winter semester of 1849-1850. A year later, His arrived at the University of Berlin, where he studied under Johannes Müller and Robert Remak. For his clinical training, His attended the University of Würzburg from 1852-1853.

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Subject: People

Karl Ernst von Baer (1792-1876)

Best known for his contributions to the field of embryology, Karl Ernst von Baer also pursued a variety of other areas of study including medicine, botany, zoology, and anthropology. Committing his life to scientific research, von Baer's work led to the advancement of the understanding of mammalian reproduction, development, and organ functioning. His embryological discoveries ultimately led him to a view of development that supported epigenesis and refuted long-held thinking about preformation.

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Subject: People

Karl Freiherr von Rokitansky (1804–1878)

During the nineteenth century, Karl Freiherr von Rokitansky conducted research on the causes of disease by performing approximately 30,000 autopsies, a practice that many people opposed at the time. Rokitansky performed his research in pathology, or the study of disease, and morbid anatomy, or the study of dead bodies, in Vienna, then part of the Austrian Empire and later part of Austria.

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Subject: People

James William Kitching (1922-2003)

James William Kitching collected and studied fossils of dinosaurs and early humans in the twentieth century. He worked at the Bernard Price Institute for Paleontological Research in South Africa. During the fifty-three years he worked at the institute, Kitching spent eighteen of those in the field uncovering fossils. Kitching recovered fossils of early human ancestors, later called Australopithecines, as well as fossils of dinosaurs and ancient mammals. When he died in 2003, the Bernard Price Institute housed one of the largest fossil collections in the southern hemisphere.

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Subject: People

William Bateson (1861-1926)

At the turn of the twentieth century, William Bateson studied organismal variation and heredity of traits within the framework of evolutionary theory in England. Bateson applied Gregor Mendel's work to Charles Darwin's theory of evolution and coined the term genetics for a new biological discipline. By studying variation and advocating Mendelian genetics, Bateson furthered the field of genetics, encouraged the use of experimental methodology to study heredity, and contributed to later theories of genetic inheritance.

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Subject: People

Victor Jollos (1887-1941)

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

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Subject: People

Theodor Heinrich Boveri (1862-1915)

Theodor Boveri investigated the mechanisms of heredity. He developed the chromosomal theory of inheritance and the idea of chromosomal individuality. Boveri sought to provide a comprehensive explanation for the hereditary role and behavior of chromosomes. He hoped that his experiments would also help to distinguish the roles of the nucleus and the cytoplasm in embryogenesis. Boveri was particularly interested in how offspring are shaped by the attributes of their parents.

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Subject: People

Eduard Friedrich Wilhelm Pflüger (1829-1910)

Eduard Friedrich Wilhelm Pflüger was a physiologist known for his research on respiration, the respiratory quotient, experimenting on the effects of electricity on muscles and nerves, and his study of the ovaries and egg development. His experiments on how the gravitational orientation of frog eggs affects their cleavage plane inspired embryologists such as Wilhelm Roux and Gustav Born to conduct their own experiments using frog eggs.

Format: Articles

Subject: People

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