Wrinch, Dorothy Maud

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Dorothy Maud Wrinch

Dorothy Maud Wrinch (1894-1976), a British mathematician, biochemist, and educator, remains known for her research into unlocking the key to protein structure through the use of mathematical principles. She is best known for developing what came to be called the "cyclol theory" of protein structure. Although the theory was later discredited, the work Wrinch did in this area has contributed to the field of genetics.

Wrinch was born on January 1, 1894, in Rosario, Argentina, a town located north of Buenos Aires on the Parana River. Her parents, Hugh Edward Hart and Ada Minnie Souter Wrinch, were British citizens.

Demonstrated Mathematical Abilities

The Wrinch family relocated to England when Wrinch was still a child, and she grew up in Surbiton, a town in Surrey, England, located near London. She attended Surbiton High, a local public day school, and won a scholarship to attend Girton College at Cambridge University, where Wrinch received her bachelor of arts degree in 1916 and her master of arts degree in 1918. In addition, when Wrinch received her graduate degree in 1918, she earned with it the ranking of wrangler in mathematics, the highest ranking possible on the final examinations in that subject.

On leaving Cambridge, Wrinch accepted a position as a lecturer in mathematics at University College in London, where she received her master of science and doctor of science degrees. She remained at University College until 1921 and then returned to Girton College when she was named a research scholar.

Wrinch went on to teach physics at Balliol College, Oxford. In 1929 she also received her doctor of science degree from the prestigious British university, becoming the first woman to attain such a degree in Oxford's history. She also received a master of arts degree from Oxford.

In 1923, while teaching at Oxford University, Wrinch married John William Nicholson, and together they had a daughter, Pamela, born in 1927. During this period, Wrinch taught mathematics at five women's colleges within communing distance from her home.

Engaged in Varied Collaborations and Associations

As the number and type of her degrees might indicate, Wrinch had a wide range of interests, among which was sociology. In addition, from 1918 to 1932 she published 20 papers on pure and applied mathematics, as well as 16 papers on scientific methodology and on the philosophy of science. During this period Wrinch also was a member of the Theoretical Biology Club founded in the 1930s at Cambridge University by Conrad Hal Waddington, the eminent embryologist and animal geneticist. The club was a multi-disciplinary group that embraced the organicist philosophy, which viewed organic life as something to be explained and understood through philosophy as well as the sciences.

Wrinch's interest in the philosophy of science resulted in a productive collaboration with eminent physicist and statistician Sir Harry Jeffreys. Jeffreys (1891-1989), who would later become regarded as the world authority in theoretical geophysics, used probability to deal with problems in the philosophy of science, viewing probability as a degree of reasonable belief. It was Wrinch who introduced him to that notion after she attended a lecture by famed mathematician Walter Ernest Johnson (1858-1931). Together, Wrinch and Jeffreys employed probability to explain induction and to investigate the soundness of various scientific theories, including general relativity. Their collaboration produced the papers "On Some Aspects of the Theory of Probability" (1919), and "On Certain Fundamental Principles of Scientific Inquiry" (1921-23). In 1931 Jeffreys wrote the book Scientific Inference in which he summarized and expanded upon his research with Wrinch.

During their years of collaboration, Wrinch and Jeffreys also developed the Simplicity Postulate, which essentially states that "the simplest law is chosen because it is the most likely to give correct predictions." In other words, simpler laws or models have the greater prior probabilities.

In keeping with her interest in sociology, as well as her experiences of motherhood, in 1930 Wrinch published a book on parenting, titled The Retreat from Parenthood, under the pen name Jean Ayling. Eventually, she would author or coauthor nearly 200 professional papers and publications.

Wrinch's marriage fell apart in the early 1930s, reportedly as a result of her husband's alcoholism. As a single woman with a child, she was badly in need of money, so she decided to increase her academic credentials to include biology, chemistry, and molecular structure. Her resourcefulness and ambition in this direction paid off, as it enabled her to secure a grant from the Rockefeller Foundation, an organization established in 1913 by John D. Rockefeller to support work in the arts and sciences. The grant would fund her research on the application of mathematics to biological molecular structures.

Developed "Cyclol" Theory

Wrinch's interest in biological molecular structures steered her into the study of genetics, specifically into her investigation into the structure of protein molecules, including egg albumin. She came to believe that protein structure held the secret of life.

In 1935 she came up with an original and controversial theory about globular protein structure. The theory, which would later become known as the "cyclol theory," advanced the concept of the cyclical model of protein structure. Specifically, the theory suggested that the specificity of the gene resides in the amino acid sequences of the gene. Wrinch based her theory on mathematical symmetry concepts and covalent bonding between two adjacent amino acids, drawing a connection between the linear sequence of the gene and the sequence of the amino acids in the poly-peptide chain. In the theory, amino acids were hooked together in chains to form a regular pattern of hexagons.

Wrinch was one of many scientists who was busy developing theories about protein structure during the same period. Some colleagues accepted her ideas while others questioned them. The cyclol theory attracted some initial and notable support from Nobel Prize-winning chemist Irving Langmuir (1881-1957). At the same time, prominent physicist John Desmond Bernal (1901-1971) strongly opposed Wrinch's theory, as he favored the hypothesis of the peptide bond, a dehydration synthesis involving a chemical bond formed between two molecules when the carboxyl group of one molecule reacts with the amino group of another. In 1938 Langmuir and Bernal entered into a debate about protein structure. This caused Langmuir to rethink his stance, and he developed the idea of a hydrophobic interaction that determined the three-dimensional structure of proteins. Soon after, Langmuir withdrew his support of Wrinch's cyclol theory.

Clashed with Linus Pauling

A much more heated debate involved Wrinch herself and famous scientist Linus Pauling (1901-1994), who would later win the Nobel Prize in Chemistry in 1954 for his work on chemical bonds, the structure of molecules and crystals, and the development of the alpha helix concept of structure proteins. Their disagreement was noted for its rancor, as it involved the clash of two forceful personalities.

Wrinch has been described as being somewhat caustic and rather aggressive in advancing her theories. She was said to be domineering in conversation and seemingly interested only in her own ideas. Pauling was viewed as being just as egocentric, if not more, and was known for alienating colleagues with his perceived arrogance, abrasiveness, and dogmatism. He was absolutely dogged in defending his work against that of other scientists. Even more, Pauling was keenly determined in his efforts to find errors in the work done by his colleagues, and he would point out these mistakes in both private and public settings.

Pauling's debate with Wrinch took place in the late 1930s, after he became chairman of the Division of Chemistry and Chemical Engineering at the California Institute of Technology. In 1937 he gave the Baker lecture at Cornell University in Ithaca, New York, and spoke about his ideas regarding proteins, which would eventually develop into his alpha helix theory. Soon after, he and Wrinch began their intense disagreement about the soundness of her cyclol theory. They met face to face in Ithaca in 1938, in a meeting that was described as hostile. The following year, Pauling wrote a paper with Carl Niemen titled "The Structure of Proteins" in which he totally discounted Wrinch's cyclol theory. The well-publicized dispute ultimately took its toll on Wrinch's research. Because Pauling continued ridiculing her theories, the result was a cut-off of her funding from the Rockefeller Foundation.

Although it was eventually proven that Wrinch's theory was indeed incorrect for proteins, her work was not in vain. It turned out that the kind of chemical bond she postulated is found in some alkaloids. Used in this new context, her research and published papers have provided valuable contributions to the field of genetics. In 1965 she published her ideas in the book Chemical Aspects of Polypeptide Chain Structure: An introduction.

Ironically, Pauling's theory, which involved the alpha helix model, also proved to be wrong. Pauling had based his model on X-ray diffraction data coupled with his experiments, which showed the peptide bond to be two-dimensional. In 1948 he fully set forth his idea that the polypeptide chain was a single-stranded helix, which he called the alpha-helix. It was left up to the famous scientific team of James Watson and Francis Crick to draw the true picture with their double-helix model.

Came to America

In 1939 Wrinch relocated to the United States when she accepted an appointment at Johns Hopkins University in Baltimore, Maryland, as a visiting lecturer in chemistry. In 1941 she accepted a joint position as visiting professor simultaneously at Amherst, Smith, and Mount Holyoke, neighboring colleges located in western Massachusetts. Wrinch remained a visiting professor at Smith College until she retired in 1971.

In the United States, Wrinch focused her new research on the application of mathematical principles to the interpretation of X-ray crystallographic data of complex crystal structures. She wrote about this work in Fourier Transforms and Structure Factors, a 96-page book published in 1946 by the American Society of X-ray Diffraction. After retiring from Smith College, Wrinch spent her last years living in Woods Hole, Massachusetts. She died in 1976.


Throughout her life, Wrinch was a prolific and eclectic writer, publishing books and numerous papers on a variety of subjects, including the interpretation of X-rays studies of crystals and proteins, the structure of protein crystals, mineralogy, scientific methodology, and the philosophy of science, probability, and mathematics. By the close of her career, she had written or co-authored close to 200 articles and publications.

Despite the erroneousness of her cyclol theory, Wrinch had a distinguished career filled with genuine accomplishments and significant recognition. In addition to being the first woman to receive a doctor of science degree from Oxford University, Wrinch was nominated for fellowship in the London Royal Society and for a Nobel Prize, although she did not receive either honor. However, her gender, coupled with her career accomplishments, placed her in unique company during her lifetime. Wrinch was one of a group of pioneering women scientists whose intellectual achievements were influential during the early part of the 20th century. These women worked in theoretical and experimental fields—areas still dominated by men—and they made major discoveries or conducted groundbreaking research. Others in this group included Dame Mary Cartwright (born 1900), the first-ever woman lecturer in mathematics at Cambridge University; crystallographer Kathleen Lonsdale (1903-73) and microbiologist Marjorie Stephenson (1880-1950), who in 1945 became the first women to be elected to the Royal Society; Cecilia Payne Gaposhkin (1900-79), the first woman to become professor of astronomy at Harvard University; and Nobel laureates Marie Curie (1903, 1911), Irene Joliot-Curie (1935), Gerty Radnitz Cori (1947), Maria Goeppert-Mayer (1963), Dorothy Hodgkin (1964), Rosalyn Yalow (1977), Barbara McClintock (1983), Rita Levi-Montalcini (1986) and Gertrude Elion (1988).


Jeffreys, Harold, Scientific Inference, Cambridge University Press, 1931.


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"Dorothy Maud Wrinch: A Multidisciplinary Researcher," Suite101.com,http://www.suite101.com/article.cfm/biographies_scientists/98637 (January 4, 2004).

"Dorothy Wrinch," SJSU Virtual Museum,http://www2.sjsu.edu/depts/Museum/wri.html (January 4, 2004).

"Harold Jeffreys as a Statistician," University of Southampton Department of Economics Web site,www.economics.soton.ac.uk/staff/aldrich/jeffreysweb.htm (January 4, 2004).

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